Single variable domain antibodies against OX40L, constructs and therapeutic use

ABSTRACT

The present invention relates to immunoglobulin single variable domain sequences that are directed against (as defined herein) OX40L, as well as to compounds or constructs, and in particular proteins and polypeptides, that comprise or essentially consist of one or more such immunoglobulin single variable domain sequences. In particular these immunoglobulin single variable domain sequences can block binding of OX40L to OX40. 
     The immunoglobulin single variable domains, compounds and constructs can be used for prophylactic, therapeutic or diagnostic purposes, such as for the treatment of inflammatory disease and/or disorder such as e.g. asthma, allergic asthma, chronic colitis, Crohn&#39;s disease, inflammatory bowel disease, and/or arthrosclerosis.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/515,876, filed Sep. 25, 2012, which is a national stage fling under35 U.S.C. §371 of international application PCT/EP2010/069606, filedDec. 14, 2010, which claims the benefit under 35 U.S.C. §119(e) of U.S.provisional application Ser. No. 61/286,163, filed Dec. 14, 2009, thedisclosures of which are incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The present invention relates to amino acid sequences that are directedagainst (as defined herein) OX40L, as well as to compounds orconstructs, and in particular proteins and polypeptides, that compriseor essentially consist of one or more such amino acid sequences (alsoreferred to herein as “amino acid sequences of the invention”,“compounds of the invention”, and “polypeptides of the invention”,respectively).

The invention also relates to nucleic acids encoding such amino acidsequences and polypeptides (also referred to herein as “nucleic acids ofthe invention” or “nucleotide sequences of the invention”); to methodsfor preparing such amino acid sequences and polypeptides; to host cellsexpressing or capable of expressing such amino acid sequences orpolypeptides; to compositions, and in particular to pharmaceuticalcompositions, that comprise such amino acid sequences, polypeptides,nucleic acids and/or host cells; and to uses of such amino acidsequences or polypeptides, nucleic acids, host cells and/orcompositions, in particular for prophylactic, therapeutic or diagnosticpurposes, such as the prophylactic, therapeutic or diagnostic purposesmentioned herein.

BACKGROUND OF THE INVENTION

Allergic diseases have reached epidemic proportions worldwide and aregenerally accepted to be increasing. Allergy symptoms are treatedefficiently with cheap small molecule drugs in most patients, but noneare curative. However, there is a clear unmet medical need for patientssuffering persistent asthma. Current standard treatment for inflammatorydiseases include immunosuppressing or immunomodulating medications suchas (but not limited to) corticosteroids, non-steroidal anti inflammatorydrugs, TNF-alpha antagonists, cytokine (receptor) agonists orantagonists. Current standard treatment for allergic asthma includeinhaled or systemically administered corticosteroids in combination withinhaled (long or short acting) Beta-2 agonists, possibly combined withmedications such as (but not limited to) Leukotriene receptorantagonists, theophylline, cromolyn, nedocromyl.

The introduction of monoclonal antibodies and soluble cytokine receptorsis revolutionizing approaches to the treatment of asthma and allergy.The successful introduction of omalizumab (anti IgE) for severe allergicasthma has stimulated great interest in this approach, but even withthis humanised monoclonal antibody, cost effectiveness analyses arerestricting its use even though it has passed scrutiny by such agents asthe National Institute of Health & Clinical Excellence in the UK. Also,substantial portions of the potential patient population in asthma haveIgE levels higher than can successfully be neutralized with the currentmolecule. A more potent inhibitor is required for these, and attemptshave been made to produce such a molecule.

Understanding the underlying mechanisms of allergic disease hasstimulated the further development of a series of biologics targetedtowards critical cells and molecules. Because of the sentinel roles ofTh2 cells and their products, Th2 cytokines, in orchestrating allergicinflammation, they and their receptors are key therapeutic targets. Oneof these is the TNF family member “OX40L” (Review: Michael J. Gough etal., Therapeutic Targets of the TNF superfamily, edited by Iqbal S.Grewal, 2007). OX40L and antibodies against OX40L which are able todisrupt binding of OX40L to its receptor OX40 (and thus inhibit therelevant signaling cascade) are mentioned in e.g. WO95/12673,WO95/21915, WO99/15200, WO2006/029879, WO2005/094879 and WO2007/133290.

SUMMARY OF THE INVENTION

Single variable domains, such as Nanobodies and dAbs and antigen bindingfragments derived therefrom are widely used to specifically target theirrespective antigens in research and therapeutic applications. However,Nanobodies and dAbs lack the Fc part and will not induce effectorfunction mediated depletion of OX40L-expressing cells and thus potentialtoxicity associated with effector function mediated depletion is not ofrelevance. However, in order to compensate for the efficacy increase bythe effector function of the full length monoclonal antibody (lacking inthe single variable domains such as Nanobodies), there is then a needfor an ultrapotent OX40L binding Nanobody or construct thereof.Furthermore, the patient group with severe persistent allergic asthmawho remain symptomatic despite optimized standard treatment, requiresignificant use of health services and are at risk of severeexacerbations including morbidity. Thus, new therapies to address theseclear and unmet needs need to be developed.

The invention has overcome the disadvantages of the prior art andaddresses the unmet medical needs.

The polypeptides and compositions of the present invention can generallybe used to modulate, and in particular inhibit and/or prevent, bindingof OX40L to OX40, and thus to modulate, and in particular inhibit orprevent, the signalling that is mediated by OX40L and/or OX40, tomodulate the biological pathways in which OX40L and/or OX40 areinvolved, and/or to modulate the biological mechanisms, responses andeffects associated with such signalling or these pathways.

As such, the polypeptides and compositions of the present invention canbe used for the prevention and treatment (as defined herein) ofinflammatory disorders such as e.g. asthma and/or allergic asthma.Generally, “inflammatory disorders such as e.g. asthma” can be definedas diseases and disorders that can be prevented and/or treated,respectively, by suitably administering to a subject in need thereof(i.e. having the disease or disorder or at least one symptom thereofand/or at risk of attracting or developing the disease or disorder) ofeither a polypeptide or composition of the invention (and in particular,of a pharmaceutically active amount thereof) and/or of a known activeprinciple active against OX40L or a biological pathway or mechanism inwhich OX40L is involved (and in particular, of a pharmaceutically activeamount thereof). Examples of such inflammatory disorders such as e.g.asthma and/or allergic asthma, will be clear to the skilled person basedon the disclosure herein, and for example include the following diseasesand disorders: rheumatoid arthritis, asthma, allergic asthma includingmoderate to severe asthma such as e.g. severe persistent asthma whosesymptoms are not adequately controlled with inhaled corticosteroids.

In particular, the polypeptides and compositions of the presentinvention can be used for the prevention and treatment of inflammatorydisorders such as e.g. asthma and/or allergic asthma which arecharacterized by excessive and/or unwanted signaling mediated by OX40Lor by the pathway(s) in which OX40L is involved. Examples of suchinflammatory disorders such as e.g. asthma and/or allergic asthma(Gough, supra), chronic colitis such as Crohn's disease (Tostuka et al.,2003, Am J Physiol Gastrointest. Liver Physiol. 284, G595-G603),inflammatory bowel disease (Souza H S et al., 1999, Gut, 45, 856-863),and/or atherosclerosis (Olofsson P. S., 2008, Circulation, 117,1291-1301) will again be clear to the skilled person. Without beinglimiting, other diseases and/or disorders associated with OX40Lincludean immune disorder and/or an autoimmune disorder (such as asthma,allergic asthma, atopic dermatitis, allergic rhinitis, inflammatorybowel disease, multiple sclerosis, graft verses host disease (GVHD),and/or systemic lupus erythematosus); a disorder associated with virus,bacteria or other infectious agent, for example virus-inducedimunopathology, e.g., pathology induced by infection with influenze orRSV or related viruses, e.g., in the lung; arthritis (acute and chronic,rheumatoid arthritis including juvenile-onset rheumatoid arthritis andstages such as rheumatoid synovitis, gout or gouty arthritis, acuteimmunological arthritis, chronic inflammatory arthritis, degenerativearthritis, type II collagen-induced arthritis, infectious arthritis,Lyme arthritis, proliferative arthritis, psoriatic arthritis, Still'sdisease, vertebral arthritis, osteoarthritis, arthritis chronicaprogrediente, arthritis deformans, polyarthritis chronica primaria,reactive arthritis, menopausal arthritis, estrogen-depletion arthritis,and ankylosing spondylitis/rheumatoid spondylitis); autoimmunelymphoproliferative disease, inflammatory hyperproliferative skindiseases, psoriasis such as plaque psoriasis, gutatte psoriasis,pustular psoriasis, and psoriasis of the nails, atopy including atopicdiseases such as hay fever and Job's syndrome, dermatitis includingcontact dermatitis, chronic contact dermatitis, exfoliative dermatitis,allergic dermatitis, allergic contact dermatitis, hives, dermatitisherpetiformis, nummular dermatitis, seborrheic dermatitis, non-specificdermatitis, primary irritant contact dermatitis, and atopic dermatitis,x-linked hyper IgM syndrome, allergic intraocular inflammatory diseases,urticaria such as chronic allergic urticaria and chronic idiopathicurticaria, including chronic autoimmune urticaria, myositis,polymyositis/dermatomyositis, juvenile dermatomyositis, toxic epidermalnecrolysis, scleroderma (including systemic scleroderma), sclerosis suchas systemic sclerosis, multiple sclerosis (MS) such as spino-optical MS,primary progressive MS (PPMS), and relapsing remitting MS (RRMS),progressive systemic sclerosis, atherosclerosis, arteriosclerosis,sclerosis disseminata, ataxic sclerosis, neuromyelitis optica (NMO),inflammatory bowel disease (IBD) (for example, Crohn's disease,autoimmune-mediated gastrointestinal diseases, gastrointestinalinflammation, colitis such as ulcerative colitis, colitis ulcerosa,microscopic colitis, collagenous colitis, colitis polyposa, necrotizingenterocolitis, and transmural colitis, and autoimmune inflammatory boweldisease), bowel inflammation, pyoderma gangrenosum, erythema nodosum,primary sclerosing cholangitis, respiratory distress syndrome, includingadult or acute respiratory distress syndrome (ARDS), meningitis,inflammation of all or part of the uvea, iritis, choroiditis, anautoimmune hematological disorder, graft-versus-host disease, angioedemasuch as hereditary angioedema, cranial nerve damage as in meningitis,herpes gestationis, pemphigoid gestationis, pruritis scroti, autoimmunepremature ovarian failure, sudden hearing loss due to an autoimmunecondition, IgE-mediated diseases such as anaphylaxis and allergic andatopic rhinitis, encephalitis such as Rasmussen's encephalitis andlimbic and/or brainstem encephalitis, uveitis, such as anterior uveitis,acute anterior uveitis, granulomatous uveitis, nongranulomatous uveitis,phacoantigenic uveitis, posterior uveitis, or autoimmune uveitis,glomerulonephritis (GN) with and without nephrotic syndrome such aschronic or acute glomerulonephritis such as primary GN, immune-mediatedGN, membranous GN (membranous nephropathy), idiopathic membranous GN oridiopathic membranous nephropathy, membrano- or membranous proliferativeGN (MPGN), including Type I and Type II, and rapidly progressive GN(RPGN), proliferative nephritis, autoimmune polyglandular endocrinefailure, balanitis including balanitis circumscripta plasmacellularis,balanoposthitis, erythema annulare centrifugum, erythema dyschromicumperstans, eythema multiform, granuloma annulare, lichen nitidus, lichensclerosus et atrophicus, lichen simplex chronicus, lichen spinulosus,lichen planus, lamellar ichthyosis, epidermolytic hyperkeratosis,premalignant keratosis, pyoderma gangrenosum, allergic conditions andresponses, food allergies, drug allergies, insect allergies, rareallergic disorders such as mastocytosis, allergic reaction, eczemaincluding allergic or atopic eczema, asteatotic eczema, dyshidroticeczema, and vesicular palmoplantar eczema, asthma such as asthmabronchiale, bronchial asthma, auto-immune asthma, allergic asthma, andpediatric asthma, conditions involving infiltration of T cells andchronic inflammatory responses, immune reactions against foreignantigens such as fetal A-B-O blood groups during pregnancy, chronicpulmonary inflammatory disease, autoimmune myocarditis, leukocyteadhesion deficiency, lupus, including lupus nephritis, lupus cerebritis,pediatric lupus, non-renal lupus, extra-renal lupus, discoid lupus anddiscoid lupus erythematosus, alopecia lupus, SLE, such as cutaneous SLEor subacute cutaneous SLE, neonatal lupus syndrome (NLE), and lupuserythematosus disseminatus, juvenile onset (Type I) diabetes mellitus,including pediatric IDDM, adult onset diabetes mellitus (Type IIdiabetes), autoimmune diabetes, idiopathic diabetes insipidus, diabeticretinopathy, diabetic nephropathy, diabetic colitis, diabeticlarge-artery disorder, immune responses associated with acute anddelayed hypersensitivity mediated by cytokines and T-lymphocytes,tuberculosis, sarcoidosis, granulomatosis including lymphomatoidgranulomatosis, Wegener's granulomatosis, agranulocytosis, vasculitides,including vasculitis, large-vessel vasculitis (including polymyalgiarheumatica and giant-cell (Takayasu's) arteritis), medium-vesselvasculitis (including Kawasaki's disease and polyarteritisnodosa/periarteritis nodosa), microscopic polyarteritis,immunovasculitis, CNS vasculitis, cutaneous vasculitis, hypersensitivityvasculitis, necrotizing vasculitis such as systemic necrotizingvasculitis, and ANCA-associated vasculitis, such as Churg-Straussvasculitis or syndrome (CSS) and ANCA-associated small-vesselvasculitis, temporal arteritis, aplastic anemia, autoimmune aplasticanemia, Coombs positive anemia, Diamond Blackfan anemia, hemolyticanemia or immune hemolytic anemia including autoimmune hemolytic anemia(AIHA), pernicious anemia (anemia perniciosa), Addison's disease, purered cell anemia or aplasia (PRCA), Factor VIII deficiency, hemophilia A,autoimmune neutropenia(s), cytopenias such as pancytopenia, leukopenia,diseases involving leukocyte diapedesis, CNS inflammatory disorders,Alzheimer's disease, Parkinson's disease, multiple organ injury syndromesuch as those secondary to septicemia, trauma or hemorrhage,antigen-antibody complex-mediated diseases, anti-glomerular basementmembrane disease, anti-phospholipid antibody syndrome, motoneuritis,allergic neuritis, Behcet's disease/syndrome, Castleman's syndrome,Goodpasture's syndrome, Reynaud's syndrome, Sjogren's syndrome,Stevens-Johnson syndrome, pemphigoid such as pemphigoid bullous and skinpemphigoid, pemphigus (including pemphigus vulgaris, pemphigusfoliaceus, pemphigus mucus-membrane pemphigoid, and pemphiguserythematosus), autoimmune polyendocrinopathies, Reiter's disease orsyndrome, thermal injury due to an autoimmune condition, preeclampsia,an immune complex disorder such as immune complex nephritis,antibody-mediated nephritis, neuroinflammatory disorders,polyneuropathies, chronic neuropathy such as IgM polyneuropathies orIgM-mediated neuropathy, thrombocytopenia (as developed by myocardialinfarction patients, for example), including thrombotic thrombocytopenicpurpura (TTP), post-transfusion purpura (PTP), heparin-inducedthrombocytopenia, and autoimmune or immune-mediated thrombocytopeniaincluding, for example, idiopathic thrombocytopenic purpura (ITP)including chronic or acute ITP, scleritis such as idiopathiccerato-scleritis, episcleritis, autoimmune disease of the testis andovary including autoimmune orchitis and oophoritis, primaryhypothyroidism, hypoparathyroidism, autoimmune endocrine diseasesincluding thyroiditis such as autoimmune thyroiditis, Hashimoto'sdisease, chronic thyroiditis (Hashimoto's thyroiditis), or subacutethyroiditis, autoimmune thyroid disease, idiopathic hypothyroidism,Grave's disease, polyglandular syndromes such as autoimmunepolyglandular syndromes, for example, type I (or polyglandularendocrinopathy syndromes), paraneoplastic syndromes, includingneurologic paraneoplastic syndromes such as Lambert-Eaton myasthenicsyndrome or Eaton-Lambert syndrome, stiff-man or stiff-person syndrome,encephalomyelitis such as allergic encephalomyelitis orencephalomyelitis allergica and experimental allergic encephalomyelitis(EAE), myasthenia gravis such as thymoma-associated myasthenia gravis,cerebellar degeneration, neuromyotonia, opsoclonus or opsoclonusmyoclonus syndrome (OMS), and sensory neuropathy, multifocal motorneuropathy, Sheehan's syndrome, autoimmune hepatitis, chronic hepatitis,lupoid hepatitis, giant-cell hepatitis, chronic active hepatitis orautoimmune chronic active hepatitis, pneumonitis such as lymphoidinterstitial pneumonitis (LIP), bronchiolitis obliterans(non-transplant) vs NSIP, Guillain-Barre syndrome, Berger's disease (IgAnephropathy), idiopathic IgA nephropathy, linear IgA dermatosis, acutefebrile neutrophilic dermatosis, subcorneal pustular dermatosis,transient acantholytic dermatosis, cirrhosis such as primary biliarycirrhosis and pneumonocirrhosis, autoimmune enteropathy syndrome, Celiacor Coeliac disease, celiac sprue (gluten enteropathy), refractory sprue,idiopathic sprue, cryoglobulinemia such as mixed cryoglobulinemia,amylotrophic lateral sclerosis (ALS; Lou Gehrig's disease), coronaryartery disease, autoimmune ear disease such as autoimmune inner eardisease (AIED), autoimmune hearing loss, polychondritis such asrefractory or relapsed or relapsing polychondritis, pulmonary alveolarproteinosis, Cogan's syndrome/nonsyphilitic interstitial keratitis,Bell's palsy, Sweet's disease/syndrome, rosacea autoimmune,zoster-associated pain, amyloidosis, a non-cancerous lymphocytosis, aprimary lymphocytosis, which includes monoclonal B cell lymphocytosis(e.g., benign monoclonal gammopathy and monoclonal gammopathy ofundetermined significance, MGUS), peripheral neuropathy, paraneoplasticsyndrome, channelopathies such as epilepsy, migraine, arrhythmia,muscular disorders, deafness, blindness, periodic paralysis, andchannelopathies of the CNS, autism, inflammatory myopathy, focal orsegmental or focal segmental glomerulosclerosis (FSGS), endocrineophthalmopathy, uveoretinitis, chorioretinitis, autoimmune hepatologicaldisorder, fibromyalgia, multiple endocrine failure, Schmidt's syndrome,adrenalitis, gastric atrophy, presenile dementia, demyelinating diseasessuch as autoimmune demyelinating diseases and chronic inflammatorydemyelinating polyneuropathy, Dressler's syndrome, alopecia areata,alopecia totalis, CREST syndrome (calcinosis, Raynaud's phenomenon,esophageal dysmotility, sclerodactyly, and telangiectasia), male andfemale autoimmune infertility, e.g., due to anti-spermatozoanantibodies, mixed connective tissue disease, Chagas' disease, rheumaticfever, recurrent abortion, farmer's lung, erythema multiforme,post-cardiotomy syndrome, Cushing's syndrome, bird-fancier's lung,allergic granulomatous angiitis, benign lymphocytic angiitis, Alport'ssyndrome, alveolitis such as allergic alveolitis and fibrosingalveolitis, interstitial lung disease, transfusion reaction, leprosy,malaria, parasitic diseases such as leishmaniasis, kypanosomiasis,schistosomiasis, ascariasis, aspergillosis, Sampter's syndrome, Caplan'ssyndrome, dengue, endocarditis, endomyocardial fibrosis, diffuseinterstitial pulmonary fibrosis, interstitial lung fibrosis, fibrosingmediastinitis, pulmonary fibrosis, idiopathic pulmonary fibrosis, cysticfibrosis, endophthalmitis, erythema elevatum et diutinum,erythroblastosis fetalis, eosinophilic faciitis, Shulman's syndrome,Felty's syndrome, flariasis, cyclitis such as chronic cyclitis,heterochronic cyclitis, iridocyclitis (acute or chronic), or Fuch'scyclitis, Henoch-Schonlein purpura, human immunodeficiency virus (HIV)infection, SCID, acquired immune deficiency syndrome (AIDS), echovirusinfection, sepsis (systemic inflammatory response syndrome (SIRS)),endotoxemia, pancreatitis, thyroxicosis, parvovirus infection, rubellavirus infection, post-vaccination syndromes, congenital rubellainfection, Epstein-Barr virus infection, mumps, Evan's syndrome,autoimmune gonadal failure, Sydenham's chorea, post-streptococcalnephritis, thromboangitis ubiterans, thyrotoxicosis, tabes dorsalis,chorioiditis, giant-cell polymyalgia, chronic hypersensitivitypneumonitis, conjunctivitis, such as vernal catarrh,keratoconjunctivitis sicca, and epidemic keratoconjunctivitis,idiopathic nephritic syndrome, minimal change nephropathy, benignfamilial and ischemia-reperfusion injury, transplant organ reperfusion,retinal autoimmunity, joint inflammation, bronchitis, chronicobstructive airway/pulmonary disease, silicosis, aphthae, aphthousstomatitis, arteriosclerotic disorders (cerebral vascular insufficiency)such as arteriosclerotic encephalopathy and arterioscleroticretinopathy, aspermiogenese, autoimmune hemolysis, Boeck's disease,cryoglobulinemia, Dupuytren's contracture, endophthalmiaphacoanaphylactica, enteritis allergica, erythema nodosum leprosum,idiopathic facial paralysis, chronic fatigue syndrome, febrisrheumatica, Hamman-Rich's disease, sensoneural hearing loss,haemoglobinuria paroxysmatica, hypogonadism, ileitis regionalis,leucopenia, mononucleosis infectiosa, traverse myelitis, primaryidiopathic myxedema, nephrosis, ophthalmia symphatica, orchitisgranulomatosa, pancreatitis, polyradiculitis acuta, pyodermagangrenosum, Quervain's thyreoiditis, acquired spenic atrophy,non-malignant thymoma, lymphofollicular thymitis, vitiligo, toxic-shocksyndrome, food poisoning, conditions involving infiltration of T cells,leukocyte-adhesion deficiency, immune responses associated with acuteand delayed hypersensitivity mediated by cytokines and T-lymphocytes,diseases involving leukocyte diapedesis, multiple organ injury syndrome,antigen-antibody complex-mediated diseases, antiglomerular basementmembrane disease, autoimmune polyendocrinopathies, oophoritis, primarymyxedema, autoimmune atrophic gastritis, sympathetic ophthalmia,rheumatic diseases, mixed connective tissue disease, nephrotic syndrome,insulitis, polyendocrine failure, autoimmune polyglandular syndromes,including polyglandular syndrome type I, adult-onset idiopathichypoparathyroidism (AOIH), cardiomyopathy such as dilatedcardiomyopathy, epidermolisis bullosa acquisita (EBA), hemochromatosis,myocarditis, nephrotic syndrome, primary sclerosing cholangitis,purulent or nonpurulent sinusitis, acute or chronic sinusitis, ethmoid,frontal, maxillary, or sphenoid sinusitis, allergic sinusitis, aneosinophil-related disorder such as eosinophilia, pulmonary infiltrationeosinophilia, eosinophilia-myalgia syndrome, Loffler's syndrome, chroniceosinophilic pneumonia, tropical pulmonary eosinophilia,bronchopneumonic aspergillosis, aspergilloma, or granulomas containingeosinophils, anaphylaxis, spondyloarthropathies, seronegativespondyloarthritides, polyendocrine autoimmune disease, sclerosingcholangitis, sclera, episclera, chronic mucocutaneous candidiasis,Bruton's syndrome, transient hypogammaglobulinemia of infancy,Wiskott-Aldrich syndrome, ataxia telangiectasia syndrome, angiectasis,autoimmune disorders associated with collagen disease, rheumatism suchas chronic arthrorheumatism, lymphadenitis, reduction in blood pressureresponse, vascular dysfunction, tissue injury, cardiovascular ischemia,hyperalgesia, renal ischemia, cerebral ischemia, and diseaseaccompanying vascularization, allergic hypersensitivity disorders,glomerulonephritides, reperfusion injury, ischemic re-perfusiondisorder, reperfusion injury of myocardial or other tissues,lymphomatous tracheobronchitis, inflammatory dermatoses, dermatoses withacute inflammatory components, multiple organ failure, bullous diseases,renal cortical necrosis, acute purulent meningitis or other centralnervous system inflammatory disorders, ocular and orbital inflammatorydisorders, granulocyte transfusion-associated syndromes,cytokine-induced toxicity, narcolepsy, acute serious inflammation,chronic intractable inflammation, pyelitis, endarterial hyperplasia,peptic ulcer, valvulitis, and endometriosis. Other examples, which insome cases encompass those listed above, include but are not limited toautoimmune rheumatologic disorders (such as, for example, rheumatoidarthritis, Sjogren's syndrome, scleroderma, lupus such as SLE and lupusnephritis, polymyositis/dermatomyositis, cryoglobulinemia,anti-phospholipid antibody syndrome, and psoriatic arthritis),autoimmune gastrointestinal and liver disorders (such as, for example,inflammatory bowel diseases (e.g., ulcerative colitis and Crohn'sdisease), autoimmune gastritis and pernicious anemia, autoimmunehepatitis, primary biliary cirrhosis, primary sclerosing cholangitis,and celiac disease), vasculitis (such as, for example, ANCA-associatedvasculitis, including Churg-Strauss vasculitis, Wegener'sgranulomatosis, and polyarteriitis), autoimmune neurological disorders(such as, for example, multiple sclerosis, opsoclonus myoclonussyndrome, myasthenia gravis, neuromyelitis optica, Parkinson's disease,Alzheimer's disease, and autoimmune polyneuropathies), renal disorders(such as, for example, glomerulonephritis, Goodpasture's syndrome, andBerger's disease), autoimmune dermatologic disorders (such as, forexample, psoriasis, urticaria, hives, pemphigus vulgaris, bullouspemphigoid, and cutaneous lupus erythematosus), hematologic disorders(such as, for example, thrombocytopenic purpura, thromboticthrombocytopenic purpura, post-transfusion purpura, and autoimmunehemolytic anemia), atherosclerosis, uveitis, autoimmune hearing diseases(such as, for example, inner ear disease and hearing loss), Behcet'sdisease, Raynaud's syndrome, organ transplant. GVHD, and autoimmuneendocrine disorders (such as, for example, diabetic-related autoimmunediseases such as insulin-dependent diabetes mellitus (IDDM), Addison'sdisease, and autoimmune thyroid disease (e.g., Graves' disease andthyroiditis)).

Thus, without being limited thereto, the amino acid sequences andpolypeptides of the invention can for example be used to prevent and/orto treat all diseases and disorders that are currently being preventedor treated with active principles that can modulate OX40L-mediatedsignalling, such as those mentioned in the prior art cited above. It isalso envisaged that the polypeptides of the invention can be used toprevent and/or to treat all diseases and disorders for which treatmentwith such active principles is currently being developed, has beenproposed, or will be proposed or developed in future. In addition, it isenvisaged that, because of their favourable properties as furtherdescribed herein, the polypeptides of the present invention may be usedfor the prevention and treatment of other diseases and disorders thanthose for which these known active principles are being used or will beproposed or developed; and/or that the polypeptides of the presentinvention may provide new methods and regimens for treating the diseasesand disorders described herein.

Other applications and uses of the amino acid sequences and polypeptidesof the invention will become clear to the skilled person from thefurther disclosure herein.

Generally, it is an object of the invention to provide pharmacologicallyactive agents, as well as compositions comprising the same, that can beused in the diagnosis, prevention and/or treatment of inflammatorydisorders such as e.g. asthma and/or allergic asthma and of the furtherdiseases and disorders mentioned herein; and to provide methods for thediagnosis, prevention and/or treatment of such diseases and disordersthat involve the administration and/or use of such agents andcompositions.

In particular, it is an object of the invention to provide suchpharmacologically active agents, compositions and/or methods that havecertain advantages compared to the agents, compositions and/or methodsthat are currently used and/or known in the art. These advantages willbecome clear from the further description below.

More in particular, it is an object of the invention to providetherapeutic proteins that can be used as pharmacologically activeagents, as well as compositions comprising the same, for the diagnosis,prevention and/or treatment of inflammatory disorders such as e.g.asthma and/or allergic asthma and of the further diseases and disordersmentioned herein; and to provide methods for the diagnosis, preventionand/or treatment of such diseases and disorders that involve theadministration and/or the use of such therapeutic proteins andcompositions.

Accordingly, it is a specific object of the present invention to provideamino acid sequences that are directed against (as defined herein)OX40L, in particular against OX40L from a warm-blooded animal, more inparticular against OX40L from a mammal such as e.g. cynomolgus OX40L(SEQ ID NO: 176), and especially against human OX40L (SEQ ID NO: 175);and to provide proteins and polypeptides comprising or essentiallyconsisting of at least one such amino acid sequence.

In particular, it is a specific object of the present invention toprovide such amino acid sequences and such proteins and/or polypeptidesthat are suitable for prophylactic, therapeutic and/or diagnostic use ina warm-blooded animal, and in particular in a mammal, and more inparticular in a human being.

More in particular, it is a specific object of the present invention toprovide such amino acid sequences and such proteins and/or polypeptidesthat can be used for the prevention, treatment, alleviation and/ordiagnosis of one or more diseases, disorders or conditions associatedwith OX40L and/or mediated by OX40L (such as the diseases, disorders andconditions mentioned herein) in a warm-blooded animal, in particular ina mammal, and more in particular in a human being.

It is also a specific object of the invention to provide such amino acidsequences and such proteins and/or polypeptides that can be used in thepreparation of pharmaceutical or veterinary compositions for theprevention and/or treatment of one or more diseases, disorders orconditions associated with and/or mediated by OX40L (such as thediseases, disorders and conditions mentioned herein) in a warm-bloodedanimal, in particular in a mammal, and more in particular in a humanbeing.

In the invention, generally, these objects are achieved by the use ofthe amino acid sequences, proteins, polypeptides and compositions thatare described herein.

In general, the invention provides amino acid sequences that aredirected against (as defined herein) and/or can specifically bind (asdefined herein) to OX40L; as well as compounds and constructs, and inparticular proteins and polypeptides, that comprise at least one suchamino acid sequence.

More in particular, the invention provides amino acid sequences that canbind to OX40L with an affinity (suitably measured and/or expressed as aK_(D)-value (actual or apparent), a K_(A)-value (actual or apparent), ak_(on)-rate and/or a k_(off)-rate, or alternatively as an IC₅₀ value, asfurther described herein) that is as defined herein; as well ascompounds and constructs, and in particular proteins and polypeptides,that comprise at least one such amino acid sequence.

In particular, amino acid sequences and polypeptides of the inventionare preferably such that they:

-   -   bind to OX40L with a dissociation constant (K_(D)) of 10⁻⁵ to        10⁻¹² moles/liter or less, and preferably 10⁻⁷ to 10⁻¹²        moles/liter or less and more preferably 10⁻⁸ to 10⁻¹²        moles/liter (i.e. with an association constant (K_(A)) of 10⁵ to        10¹² liter/moles or more, and preferably 10⁷ to 10¹² liter/moles        or more and more preferably 10⁸ to 10¹² liter/moles);        and/or such that they:    -   bind to OX40L with a k_(on)-rate of between 10² M⁻¹s⁻¹ to about        10⁷ preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more        preferably between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between        10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹;        and/or such that they:    -   bind to OX40L with a k_(off) rate between 1 s⁻¹ (t_(1/2)=0.69 s)        and 10⁻⁶s⁻¹ (providing a near irreversible complex with a        t_(1/2) of multiple days), preferably between 10⁻² s⁻¹ and        10⁻⁶s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as        between 10⁻⁴s⁻¹ and 10⁻⁶ s⁻¹.

Preferably, a monovalent amino acid sequence of the invention (or apolypeptide that contains only one amino acid sequence of the invention)is preferably such that it will bind to OX40L with an affinity less than500 nM, preferably less than 200 nM, more preferably less than 10 nM,such as less than 500 pM.

Some preferred IC50 values for binding of the amino acid sequences orpolypeptides of the invention to OX40L will become clear from thefurther description and examples herein.

For binding to OX40L, an amino acid sequence of the invention willusually contain within its amino acid sequence one or more amino acidresidues or one or more stretches of amino acid residues (i.e. with each“stretch” comprising two or amino acid residues that are adjacent toeach other or in close proximity to each other, i.e. in the primary ortertiary structure of the amino acid sequence) via which the amino acidsequence of the invention can bind to OX40L, which amino acid residuesor stretches of amino acid residues thus form the “site” for binding toOX40L (also referred to herein as the “antigen binding site”).

The amino acid sequences provided by the invention are preferably inessentially isolated form (as defined herein), or form part of a proteinor polypeptide of the invention (as defined herein), which may compriseor essentially consist of one or more amino acid sequences of theinvention and which may optionally further comprise one or more furtheramino acid sequences (all optionally linked via one or more suitablelinkers). For example, and without limitation, the one or more aminoacid sequences of the invention may be used as a binding unit in such aprotein or polypeptide, which may optionally contain one or more furtheramino acid sequences that can serve as a binding unit (i.e. against oneor more other targets than OX40L), so as to provide a monovalent,multivalent or multispecific polypeptide of the invention, respectively,all as described herein. Such a protein or polypeptide may also be inessentially isolated form (as defined herein).

The amino acid sequences and polypeptides of the invention as suchpreferably essentially consist of a single amino acid chain that is notlinked via disulphide bridges to any other amino acid sequence or chain(but that may or may not contain one or more intramolecular disulphidebridges. For example, it is known that Nanobodies—as describedherein—may sometimes contain a disulphide bridge between CDR3 and CDR1or FR2). However, it should be noted that one or more amino acidsequences of the invention may be linked to each other and/or to otheramino acid sequences (e.g. via disulphide bridges) to provide peptideconstructs that may also be useful in the invention (for example Fab′fragments, F(ab′)₂ fragments, ScFv constructs, “diabodies” and othermultispecific constructs. Reference is for example made to the review byHolliger and Hudson, Nat Biotechnol. 2005 September; 23(9):1126-36).

Generally, when an amino acid sequence of the invention (or a compound,construct or polypeptide comprising the same) is intended foradministration to a subject (for example for therapeutic and/ordiagnostic purposes as described herein), it is preferably either anamino acid sequence that does not occur naturally in said subject; or,when it does occur naturally in said subject, in essentially isolatedform (as defined herein).

It will also be clear to the skilled person that for pharmaceutical use,the amino acid sequences of the invention (as well as compounds,constructs and polypeptides comprising the same) are preferably directedagainst human OX40L; whereas for veterinary purposes, the amino acidsequences and polypeptides of the invention are preferably directedagainst OX40L from the species to be treated, or at least cross-reactivewith OX40L from the species to be treated.

Furthermore, an amino acid sequence of the invention may optionally, andin addition to the at least one binding site for binding against OX40L,contain one or more further binding sites for binding against otherantigens, proteins or targets.

The efficacy of the amino acid sequences and polypeptides of theinvention, and of compositions comprising the same, can be tested usingany suitable in vitro assay, cell-based assay, in vivo assay and/oranimal model known per se, or any combination thereof, depending on thespecific disease or disorder involved. Suitable assays and animal modelswill be clear to the skilled person, and for example include Ascarissuum model for asthma in monkey, as well as the assays and animal modelsused in the experimental part below and in the prior art cited herein.

Also, according to the invention, amino acid sequences and polypeptidesthat are directed against OX40L from a first species of warm-bloodedanimal may or may not show cross-reactivity with OX40L from one or moreother species of warm-blooded animal. For example, amino acid sequencesand polypeptides directed against human OX40L may or may not show crossreactivity with OX40L from one or more other species of primates (suchas, without limitation, monkeys from the genus Macaca (such as, and inparticular, cynomolgus monkeys (Macaca fascicularis) and/or rhesusmonkeys (Macaca mulatta)) and baboon (Papio ursinus)) and/or with OX40Lfrom one or more species of animals that are often used in animal modelsfor diseases (for example mouse, rat, rabbit, pig or dog), and inparticular in animal models for diseases and disorders associated withOX40L (such as the species and animal models mentioned herein). In thisrespect, it will be clear to the skilled person that suchcross-reactivity, when present, may have advantages from a drugdevelopment point of view, since it allows the amino acid sequences andpolypeptides against human OX40L to be tested in such disease models.

More generally, amino acid sequences and polypeptides of the inventionthat are cross-reactive with OX40L from multiple species of mammal willusually be advantageous for use in veterinary applications, since itwill allow the same amino acid sequence or polypeptide to be used acrossmultiple species. Thus, it is also encompassed within the scope of theinvention that amino acid sequences and polypeptides directed againstOX40L from one species of animal (such as amino acid sequences andpolypeptides against human OX40L) can be used in the treatment ofanother species of animal, as long as the use of the amino acidsequences and/or polypeptides provide the desired effects in the speciesto be treated.

The present invention is in its broadest sense also not particularlylimited to or defined by a specific antigenic determinant, epitope,part, domain, subunit or confirmation (where applicable) of OX40Lagainst which the amino acid sequences and polypeptides of the inventionare directed. For example, the amino acid sequences and polypeptides mayor may not be directed against an “interaction site” (as definedherein). However, it is generally assumed and preferred that the aminoacid sequences and polypeptides of the invention are preferably directedagainst an interaction site (as defined herein), and in particularagainst one or more epitopes of Nanobodies as described herein, e.g. oneor more epitopes of Nanobody 01B11 (SEQ ID NO: 179), 18E09 (SEQ ID NO:183) and 15B07 (SEQ ID NO: 182). Thus, in one preferred, butnon-limiting aspect, the amino acid sequences and polypeptides of theinvention are directed against one or more epitopes of Nanobody 01B11(SEQ ID NO: 179), 18E09 (SEQ ID NO: 183) and 15B07 (SEQ ID NO: 182) andare as further defined herein.

As further described herein, a polypeptide of the invention may containtwo or more amino acid sequences of the invention that are directedagainst OX40L. Generally, such polypeptides will bind to OX40L withincreased avidity compared to a single amino acid sequence of theinvention. Such a polypeptide may for example comprise two amino acidsequences of the invention that are directed against the same antigenicdeterminant, epitope, part, domain, subunit or confirmation (whereapplicable) of OX40L (which may or may not be an interaction site); orcomprise at least one “first” amino acid sequence of the invention thatis directed against a first antigenic determinant, epitope, part,domain, subunit or confirmation (where applicable) of OX40L (which mayor may not be an interaction site); and at least one “second” amino acidsequence of the invention that is directed against a second antigenicdeterminant, epitope, part, domain, subunit or confirmation (whereapplicable) different from the first (and which again may or may not bean interaction site). Preferably, in such “biparatopic” polypeptides ofthe invention, at least one amino acid sequence of the invention isdirected against an interaction site (as defined herein), although theinvention in its broadest sense is not limited thereto.

Also, when the target is part of a binding pair (for example, areceptor-ligand binding pair), the amino acid sequences and polypeptidesmay be such that they compete with the cognate binding partner (e.g. theligand, receptor or other binding partner, as applicable) for binding tothe target, and/or such that they (fully or partially) neutralizebinding of the binding partner to the target.

It is also within the scope of the invention that, where applicable, anamino acid sequence of the invention can bind to two or more antigenicdeterminants, epitopes, parts, domains, subunits or confirmations ofOX40L. In such a case, the antigenic determinants, epitopes, parts,domains or subunits of OX40L to which the amino acid sequences and/orpolypeptides of the invention bind may be essentially the same (forexample, if OX40L contains repeated structural motifs or occurs in amultimeric form) or may be different (and in the latter case, the aminoacid sequences and polypeptides of the invention may bind to suchdifferent antigenic determinants, epitopes, parts, domains, subunits ofOX40L with an affinity and/or specificity which may be the same ordifferent). Also, for example, when OX40L exists in an activatedconformation and in an inactive conformation, the amino acid sequencesand polypeptides of the invention may bind to either one of theseconfirmation, or may bind to both these confirmations (i.e. with anaffinity and/or specificity which may be the same or different). Also,for example, the amino acid sequences and polypeptides of the inventionmay bind to a conformation of OX40L in which it is bound to a pertinentligand, may bind to a conformation of OX40L in which it not bound to apertinent ligand, or may bind to both such conformations (again with anaffinity and/or specificity which may be the same or different).

It is also expected that the amino acid sequences and polypeptides ofthe invention will generally bind to all naturally occurring orsynthetic analogs, variants, mutants, alleles, parts and fragments ofOX40L; or at least to those analogs, variants, mutants, alleles, partsand fragments of OX40L that contain one or more antigenic determinantsor epitopes that are essentially the same as the antigenicdeterminant(s) or epitope(s) to which the amino acid sequences andpolypeptides of the invention bind in OX40L (e.g. in wild-type OX40L).Again, in such a case, the amino acid sequences and polypeptides of theinvention may bind to such analogs, variants, mutants, alleles, partsand fragments with an affinity and/or specificity that are the same as,or that are different from (i.e. higher than or lower than), theaffinity and specificity with which the amino acid sequences of theinvention bind to (wild-type) OX40L. It is also included within thescope of the invention that the amino acid sequences and polypeptides ofthe invention bind to some analogs, variants, mutants, alleles, partsand fragments of OX40L, but not to others.

When OX40L exists in a monomeric form and in one or more multimericforms, it is within the scope of the invention that the amino acidsequences and polypeptides of the invention only bind to OX40L inmonomeric form, only bind to OX40L in multimeric form, or bind to boththe monomeric and the multimeric form. Again, in such a case, the aminoacid sequences and polypeptides of the invention may bind to themonomeric form with an affinity and/or specificity that are the same as,or that are different from (i.e. higher than or lower than), theaffinity and specificity with which the amino acid sequences of theinvention bind to the multimeric form.

Also, when OX40L can associate with other proteins or polypeptides toform protein complexes (e.g. with multiple subunits), it is within thescope of the invention that the amino acid sequences and polypeptides ofthe invention bind to OX40L in its non-associated state, bind to OX40Lin its associated state, or bind to both. In all these cases, the aminoacid sequences and polypeptides of the invention may bind to suchmultimers or associated protein complexes with an affinity and/orspecificity that may be the same as or different from (i.e. higher thanor lower than) the affinity and/or specificity with which the amino acidsequences and polypeptides of the invention bind to OX40L in itsmonomeric and non-associated state.

Also, as will be clear to the skilled person, proteins or polypeptidesthat contain two or more amino acid sequences directed against OX40L maybind with higher avidity to OX40L than the corresponding monomeric aminoacid sequence(s). For example, and without limitation, proteins orpolypeptides that contain two or more amino acid sequences directedagainst different epitopes of OX40L may (and usually will) bind withhigher avidity than each of the different monomers, and proteins orpolypeptides that contain two or more amino acid sequences directedagainst OX40L may (and usually will) bind also with higher avidity to amultimer of OX40L.

Generally, amino acid sequences and polypeptides of the invention willat least bind to those forms of OX40L (including monomeric, multimericand associated forms) that are the most relevant from a biologicaland/or therapeutic point of view, as will be clear to the skilledperson.

It is also within the scope of the invention to use parts, fragments,analogs, mutants, variants, alleles and/or derivatives of the amino acidsequences and polypeptides of the invention, and/or to use proteins orpolypeptides comprising or essentially consisting of one or more of suchparts, fragments, analogs, mutants, variants, alleles and/orderivatives, as long as these are suitable for the uses envisagedherein. Such parts, fragments, analogs, mutants, variants, allelesand/or derivatives will usually contain (at least part of) a functionalantigen-binding site for binding against OX40L; and more preferably willbe capable of specific binding to OX40L, and even more preferablycapable of binding to OX40L with an affinity (suitably measured and/orexpressed as a K_(D)-value (actual or apparent), a K_(A)-value (actualor apparent), a k_(on)-rate and/or a k_(off)-rate, or alternatively asan IC₅₀ value, as further described herein) that is as defined herein.Some non-limiting examples of such parts, fragments, analogs, mutants,variants, alleles, derivatives, proteins and/or polypeptides will becomeclear from the further description herein. Additional fragments orpolypeptides of the invention may also be provided by suitably combining(i.e. by linking or genetic fusion) one or more (smaller) parts orfragments as described herein.

In one specific, but non-limiting aspect of the invention, which will befurther described herein, such analogs, mutants, variants, alleles,derivatives have an increased half-life in serum (as further describedherein) compared to the amino acid sequence from which they have beenderived. For example, an amino acid sequence of the invention may belinked (chemically or otherwise) to one or more groups or moieties thatextend the half-life (such as PEG), so as to provide a derivative of anamino acid sequence of the invention with increased half-life.

In one specific, but non-limiting aspect, the amino acid sequence of theinvention may be an amino acid sequence that comprises an immunoglobulinfold or may be an amino acid sequence that, under suitable conditions(such as physiological conditions) is capable of forming animmunoglobulin fold (i.e. by folding). Reference is inter alia made tothe review by Halaby et al., J. (1999) Protein Eng. 12, 563-71.Preferably, when properly folded so as to form an immunoglobulin fold,such an amino acid sequence is capable of specific binding (as definedherein) to OX40L; and more preferably capable of binding to OX40L withan affinity (suitably measured and/or expressed as a K_(D)-value (actualor apparent), a K_(A)-value (actual or apparent), a k_(on)-rate and/or ak_(off)-rate, or alternatively as an IC₅₀ value, as further describedherein) that is as defined herein. Also, parts, fragments, analogs,mutants, variants, alleles and/or derivatives of such amino acidsequences are preferably such that they comprise an immunoglobulin foldor are capable for forming, under suitable conditions, an immunoglobulinfold.

In particular, but without limitation, the amino acid sequences of theinvention may be amino acid sequences that essentially consist of 4framework regions (FR1 to FR4 respectively) and 3 complementaritydetermining regions (CDR1 to CDR3 respectively); or any suitablefragment of such an amino acid sequence (which will then usually containat least some of the amino acid residues that form at least one of theCDR's, as further described herein).

The amino acid sequences of the invention may in particular be animmunoglobulin sequence or a suitable fragment thereof, and more inparticular be an immunoglobulin variable domain sequence, immunoglobulinsingle variable domain sequences or a suitable fragment thereof, such aslight chain variable domain sequence (e.g. a V_(L)-sequence) or asuitable fragment thereof; or a heavy chain variable domain sequence(e.g. a V_(H)-sequence) or a suitable fragment thereof. When the aminoacid sequence of the invention is a heavy chain variable domainsequence, it may be a heavy chain variable domain sequence that isderived from a conventional four-chain antibody (such as, withoutlimitation, a V_(H) sequence that is derived from a human antibody) orbe a so-called V_(HH)-sequence (as defined herein) that is derived froma so-called “heavy chain antibody” (as defined herein).

However, it should be noted that the invention is not limited as to theorigin of the amino acid sequence of the invention (or of the nucleotidesequence of the invention used to express it), nor as to the way thatthe amino acid sequence or nucleotide sequence of the invention is (orhas been) generated or obtained. Thus, the amino acid sequences of theinvention may be naturally occurring amino acid sequences (from anysuitable species) or synthetic or semi-synthetic amino acid sequences.In a specific but non-limiting aspect of the invention, the amino acidsequence is a naturally occurring immunoglobulin sequence (from anysuitable species) or a synthetic or semi-synthetic immunoglobulinsequence, including but not limited to “humanized” (as defined herein)immunoglobulin sequences (such as partially or fully humanized mouse orrabbit immunoglobulin sequences, and in particular partially or fullyhumanized V_(HH) sequences or Nanobodies), “camelized” (as definedherein) immunoglobulin sequences, as well as immunoglobulin sequencesthat have been obtained by techniques such as affinity maturation (forexample, starting from synthetic, random or naturally occurringimmunoglobulin sequences), CDR grafting, veneering, combining fragmentsderived from different immunoglobulin sequences, PCR assembly usingoverlapping primers, and similar techniques for engineeringimmunoglobulin sequences well known to the skilled person; or anysuitable combination of any of the foregoing. Reference is for examplemade to the standard handbooks, as well as to the further descriptionand prior art mentioned herein.

Similarly, the nucleotide sequences of the invention may be naturallyoccurring nucleotide sequences or synthetic or semi-synthetic sequences,and may for example be sequences that are isolated by PCR from asuitable naturally occurring template (e.g. DNA or RNA isolated from acell), nucleotide sequences that have been isolated from a library (andin particular, an expression library), nucleotide sequences that havebeen prepared by introducing mutations into a naturally occurringnucleotide sequence (using any suitable technique known per se, such asmismatch PCR), nucleotide sequence that have been prepared by PCR usingoverlapping primers, or nucleotide sequences that have been preparedusing techniques for DNA synthesis known per se.

The amino acid sequence of the invention may in particular be animmunoglobulin single variable domain sequence such as a domain antibody(or an amino acid sequence that is suitable for use as a domainantibody), a single domain antibody (or an amino acid sequence that issuitable for use as a single domain antibody), a “dAb” (or an amino acidsequence that is suitable for use as a dAb) or a Nanobody (as definedherein, and including but not limited to a V_(HH) sequence); othersingle variable domains, or any suitable fragment of any one thereof.For a general description of (single) domain antibodies, reference isalso made to the prior art cited above, as well as to EP 0 368 684. Forthe term “dAb's”, reference is for example made to Ward et al. (Nature1989 Oct. 12; 341 (6242): 544-6), to Holt et al., Trends Biotechnol.,2003, 21(11):484-490; as well as to for example WO 06/030220, WO06/003388 and other published patent applications of Domantis Ltd. Itshould also be noted that, although less preferred in the context of thepresent invention because they are not of mammalian origin, singledomain antibodies or single variable domains can be derived from certainspecies of shark (for example, the so-called “IgNAR domains”, see forexample WO 05/18629).

In particular, the amino acid sequence of the invention may be aNanobody® (as defined herein) or a suitable fragment thereof. [Note:Nanobody®, Nanobodies® and Nanoclone® are registered trademarks ofAblynx N.V.] Such Nanobodies directed against OX40L will also bereferred to herein as “Nanobodies of the invention”.

For a general description of Nanobodies, reference is made to thefurther description below, as well as to the prior art cited herein. Inthis respect, it should however be noted that this description and theprior art mainly described Nanobodies of the so-called “V_(H)3 class”(i.e. Nanobodies with a high degree of sequence homology to humangermline sequences of the V_(H)3 class such as DP-47, DP-51 or DP-29),which Nanobodies form a preferred aspect of this invention. It shouldhowever be noted that the invention in its broadest sense generallycovers any type of Nanobody directed against OX40L, and for example alsocovers the Nanobodies belonging to the so-called “V_(H)4 class” (i.e.Nanobodies with a high degree of sequence homology to human germlinesequences of the V_(H)4 class such as DP-78), as for example describedin WO 07/118670.

Generally, Nanobodies (in particular V_(HH) sequences and partiallyhumanized Nanobodies) can in particular be characterized by the presenceof one or more “Hallmark residues” (as described herein) in one or moreof the framework sequences (again as further described herein).

Thus, generally, a Nanobody can be defined as an amino acid sequencewith the (general) structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which one or more of the Hallmark residues are as further        defined herein.

In particular, a Nanobody can be an amino acid sequence with the(general) structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which the framework sequences are as further defined herein.

More in particular, a Nanobody can be an amino acid sequence with the(general) structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   i) preferably one or more of the amino acid residues at positions    11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according to the Kabat    numbering are chosen from the Hallmark residues mentioned in Table    B-2 below;    and in which:

-   ii) said amino acid sequence has at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 1 to    22, in which for the purposes of determining the degree of amino    acid identity, the amino acid residues that form the CDR sequences    (indicated with X in the sequences of SEQ ID NO's: 1 to 22) are    disregarded.

In these Nanobodies, the CDR sequences are generally as further definedherein.

Thus, the invention also relates to such Nanobodies that can bind to (asdefined herein) and/or are directed against OX40L, to suitable fragmentsthereof, as well as to polypeptides that comprise or essentially consistof one or more of such Nanobodies and/or suitable fragments.

SEQ ID NO's: 179 to 185 (see Table A-1) give the amino acid sequences ofa number of V_(HH) sequences that have been raised against OX40L.

In particular, the invention in some specific aspects provides:

-   -   amino acid sequences that are directed against (as defined        herein) OX40L and that have at least 80%, preferably at least        85%, such as 90% or 95% or more sequence identity with at least        one of the amino acid sequences of SEQ ID NO's: 179 to 185 (see        Table A-1). These amino acid sequences may further be such that        they neutralize binding of the cognate ligand or receptor to        OX40L; and/or compete with the cognate ligand or receptor for        binding to OX40L; and/or are directed against an interaction        site (as defined herein) on OX40L (such as the ligand or        receptor binding site);    -   amino acid sequences that cross-block (as defined herein) the        binding of at least one of the amino acid sequences of SEQ ID        NO's: 179 to 185 (see Table A-1) to OX40L and/or that compete        with at least one of the amino acid sequences of SEQ ID NO's:        179 to 185 (see Table A-1) for binding to OX40L. Again, these        amino acid sequences may further be such that they neutralize        binding of the cognate ligand or receptor to OX40L; and/or        compete with the cognate ligand or receptor for binding to        OX40L; and/or are directed against an interaction site (as        defined herein) on OX40L (such as the ligand or receptor binding        site);        which amino acid sequences may be as further described herein        (and may for example be Nanobodies); as well as polypeptides of        the invention that comprise one or more of such amino acid        sequences (which may be as further described herein, and may for        example be bispecific and/or biparatopic polypeptides as        described herein), and nucleic acid sequences that encode such        amino acid sequences and polypeptides. Such amino acid sequences        and polypeptides do not include any naturally occurring ligands.

In some other specific aspects, the invention provides:

-   -   amino acid sequences of the invention that are specific for        OX40L compared to other members of the TNF family;        which amino acid sequences of the invention may be as further        described herein (and may for example be Nanobodies); as well as        polypeptides of the invention that comprise one or more of such        amino acid sequences (which may be as further described herein,        and may for example be bispecific and/or biparatopic        polypeptides as described herein), and nucleic acid sequences        that encode such amino acid sequences and polypeptides. Such        amino acid sequences and polypeptides do not include any        naturally occurring ligands.

Accordingly, some particularly preferred Nanobodies of the invention areNanobodies which can bind (as further defined herein) to and/or aredirected against to OX40L and which:

-   i) have at least 80% amino acid identity with at least one of the    amino acid sequences of SEQ ID NO's: 179 to 185 (see Table A-1), in    which for the purposes of determining the degree of amino acid    identity, the amino acid residues that form the CDR sequences are    disregarded. In this respect, reference is also made to Table B-1,    which lists the framework 1 sequences (SEQ ID NO's: 126 to 132),    framework 2 sequences (SEQ ID NO's: 140 to 146), framework 3    sequences (SEQ ID NO's: 154 to 160) and framework 4 sequences (SEQ    ID NO's: 168 to 174) of the Nanobodies of SEQ ID NO's: 179 to 185    (see Table A-1) (with respect to the amino acid residues at    positions 1 to 4 and 27 to 30 of the framework 1 sequences,    reference is also made to the comments made below. Thus, for    determining the degree of amino acid identity, these residues are    preferably disregarded);    and in which:-   ii) preferably one or more of the amino acid residues at positions    11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according to the Kabat    numbering are chosen from the Hallmark residues mentioned in Table    B-2 below.

In these Nanobodies, the CDR sequences are generally as further definedherein.

Again, such Nanobodies may be derived in any suitable manner and fromany suitable source, and may for example be naturally occurring V_(HH)sequences (i.e. from a suitable species of Camelid) or synthetic orsemi-synthetic amino acid sequences, including but not limited to“humanized” (as defined herein) Nanobodies, “camelized” (as definedherein) immunoglobulin sequences (and in particular camelized heavychain variable domain sequences), as well as Nanobodies that have beenobtained by techniques such as affinity maturation (for example,starting from synthetic, random or naturally occurring immunoglobulinsequences), CDR grafting, veneering, combining fragments derived fromdifferent immunoglobulin sequences, PCR assembly using overlappingprimers, and similar techniques for engineering immunoglobulin sequenceswell known to the skilled person; or any suitable combination of any ofthe foregoing as further described herein. Also, when a Nanobodycomprises a V_(HH) sequence, said Nanobody may be suitably humanized, asfurther described herein, so as to provide one or more further(partially or fully) humanized Nanobodies of the invention. Similarly,when a Nanobody comprises a synthetic or semi-synthetic sequence (suchas a partially humanized sequence), said Nanobody may optionally befurther suitably humanized, again as described herein, again so as toprovide one or more further (partially or fully) humanized Nanobodies ofthe invention.

In particular, humanized Nanobodies may be amino acid sequences that areas generally defined for Nanobodies in the previous paragraphs, but inwhich at least one amino acid residue is present (and in particular, inat least one of the framework residues) that is and/or that correspondsto a humanizing substitution (as defined herein). Some preferred, butnon-limiting humanizing substitutions (and suitable combinationsthereof) will become clear to the skilled person based on the disclosureherein. In addition, or alternatively, other potentially usefulhumanizing substitutions can be ascertained by comparing the sequence ofthe framework regions of a naturally occurring V_(HH) sequence with thecorresponding framework sequence of one or more closely related humanV_(H) sequences, after which one or more of the potentially usefulhumanizing substitutions (or combinations thereof) thus determined canbe introduced into said V_(HH) sequence (in any manner known per se, asfurther described herein) and the resulting humanized V_(HH) sequencescan be tested for affinity for the target, for stability, for ease andlevel of expression, and/or for other desired properties. In this way,by means of a limited degree of trial and error, other suitablehumanizing substitutions (or suitable combinations thereof) can bedetermined by the skilled person based on the disclosure herein. Also,based on the foregoing, (the framework regions of) a Nanobody may bepartially humanized or fully humanized.

Some particularly preferred humanized Nanobodies of the invention arehumanized variants of the Nanobodies of SEQ ID NO's: 179 to 185 (seeTable A-1), of which the amino acid sequences of SEQ ID NO's: 199 to 226(see Table A-2) are some especially preferred examples.

According to another specific aspect of the invention, the inventionprovides a number of stretches of amino acid residues (i.e. smallpeptides) that are particularly suited for binding to OX40L. Thesestretches of amino acid residues may be present in, and/or may beincorporated into, an amino acid sequence of the invention, inparticular in such a way that they form (part of) the antigen bindingsite of an amino acid sequence of the invention. As these stretches ofamino acid residues were first generated as CDR sequences of heavy chainantibodies or V_(HH) sequences that were raised against OX40L (or may bebased on and/or derived from such CDR sequences, as further describedherein), they will also generally be referred to herein as “CDRsequences” (i.e. as CDR1 sequences, CDR2 sequences and CDR3 sequences,respectively). It should however be noted that the invention in itsbroadest sense is not limited to a specific structural role or functionthat these stretches of amino acid residues may have in an amino acidsequence of the invention, as long as these stretches of amino acidresidues allow the amino acid sequence of the invention to bind toOX40L. Thus, generally, the invention in its broadest sense comprisesany amino acid sequence that is capable of binding to OX40L and thatcomprises one or more CDR sequences as described herein, and inparticular a suitable combination of two or more such CDR sequences,that are suitably linked to each other via one or more further aminoacid sequences, such that the entire amino acid sequence forms a bindingdomain and/or binding unit that is capable of binding to OX40L. Itshould however also be noted that the presence of only one such CDRsequence in an amino acid sequence of the invention may by itselfalready be sufficient to provide an amino acid sequence of the inventionthat is capable of binding to OX40L; reference is for example again madeto the so-called “Expedite fragments” described in WO 03/050531 orWO2009/127691.

Thus, in another specific, but non-limiting aspect, the amino acidsequence of the invention may be an amino acid sequence that comprisesat least one amino acid sequence that is chosen from the groupconsisting of the CDR1 sequences, CDR2 sequences and CDR3 sequences thatare described herein (or any suitable combination thereof). Inparticular, an amino acid sequence of the invention may be an amino acidsequence that comprises at least one antigen binding site, wherein saidantigen binding site comprises at least one amino acid sequence that ischosen from the group consisting of the CDR1 sequences, CDR2 sequencesand CDR3 sequences that are described herein (or any suitablecombination thereof).

Generally, in this aspect of the invention, the amino acid sequence ofthe invention may be any amino acid sequence that comprises at least onestretch of amino acid residues, in which said stretch of amino acidresidues has an amino acid sequence that corresponds to the sequence ofat least one of the CDR sequences described herein. Such an amino acidsequence may or may not comprise an immunoglobulin fold. For example,and without limitation, such an amino acid sequence may be a suitablefragment of an immunoglobulin sequence that comprises at least one suchCDR sequence, but that is not large enough to form a (complete)immunoglobulin fold (reference is for example again made to the“Expedite fragments” described in WO03/050531 or WO2009/127691).Alternatively, such an amino acid sequence may be a suitable “proteinscaffold” that comprises at least one stretch of amino acid residuesthat corresponds to such a CDR sequence (i.e. as part of its antigenbinding site). Suitable scaffolds for presenting amino acid sequenceswill be clear to the skilled person, and for example comprise, withoutlimitation, to binding scaffolds based on or derived fromimmunoglobulins (i.e. other than the immunoglobulin sequences alreadydescribed herein), protein scaffolds derived from protein A domains(such as Affibodies™), tendamistat, fibronectin, lipocalin, CTLA-4,T-cell receptors, designed ankyrin repeats, avimers and PDZ domains(Binz et al., Nat. Biotech 2005, Vol 23:1257), and binding moietiesbased on DNA or RNA including but not limited to DNA or RNA aptamers(Ulrich et al., Comb Chem High Throughput Screen 2006 9(8):619-32).

Again, any amino acid sequence of the invention that comprises one ormore of these CDR sequences is preferably such that it can specificallybind (as defined herein) to OX40L, and more in particular such that itcan bind to OX40L with an affinity (suitably measured and/or expressedas a K_(D)-value (actual or apparent), a K_(A)-value (actual orapparent), a k_(on)-rate and/or a k_(off)-rate, or alternatively as anIC₅₀ value, as further described herein), that is as defined herein.

More in particular, the amino acid sequences according to this aspect ofthe invention may be any amino acid sequence that comprises at least oneantigen binding site, wherein said antigen binding site comprises atleast two amino acid sequences that are chosen from the group consistingof the CDR1 sequences described herein, the CDR2 sequences describedherein and the CDR3 sequences described herein, such that (i) when thefirst amino acid sequence is chosen from the CDR1 sequences describedherein, the second amino acid sequence is chosen from the CDR2 sequencesdescribed herein or the CDR3 sequences described herein; (ii) when thefirst amino acid sequence is chosen from the CDR2 sequences describedherein, the second amino acid sequence is chosen from the CDR1 sequencesdescribed herein or the CDR3 sequences described herein; or (iii) whenthe first amino acid sequence is chosen from the CDR3 sequencesdescribed herein, the second amino acid sequence is chosen from the CDR1sequences described herein or the CDR3 sequences described herein.

Even more in particular, the amino acid sequences of the invention maybe amino acid sequences that comprise at least one antigen binding site,wherein said antigen binding site comprises at least three amino acidsequences that are chosen from the group consisting of the CDR1sequences described herein, the CDR2 sequences described herein and theCDR3 sequences described herein, such that the first amino acid sequenceis chosen from the CDR1 sequences described herein, the second aminoacid sequence is chosen from the CDR2 sequences described herein, andthe third amino acid sequence is chosen from the CDR3 sequencesdescribed herein. Preferred combinations of CDR1, CDR2 and CDR3sequences will become clear from the further description herein. As willbe clear to the skilled person, such an amino acid sequence ispreferably an immunoglobulin sequence (as further described herein), butit may for example also be any other amino acid sequence that comprisesa suitable scaffold for presenting said CDR sequences.

Thus, in one specific, but non-limiting aspect, the invention relates toan amino acid sequence directed against OX40L, that comprises one ormore stretches of amino acid residues chosen from the group consistingof:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;    or any suitable combination thereof.

When an amino acid sequence of the invention contains one or more aminoacid sequences according to b) and/or c):

-   i) any amino acid substitution in such an amino acid sequence    according to b) and/or c) is preferably, and compared to the    corresponding amino acid sequence according to a), a conservative    amino acid substitution, (as defined herein);    and/or-   ii) the amino acid sequence according to b) and/or c) preferably    only contains amino acid substitutions, and no amino acid deletions    or insertions, compared to the corresponding amino acid sequence    according to a);    and/or-   iii) the amino acid sequence according to b) and/or c) may be an    amino acid sequence that is derived from an amino acid sequence    according to a) by means of affinity maturation using one or more    techniques of affinity maturation known per se.

Similarly, when an amino acid sequence of the invention contains one ormore amino acid sequences according to e) and/or f):

-   i) any amino acid substitution in such an amino acid sequence    according to e) and/or f) is preferably, and compared to the    corresponding amino acid sequence according to d), a conservative    amino acid substitution, (as defined herein);    and/or-   ii) the amino acid sequence according to e) and/or f) preferably    only contains amino acid substitutions, and no amino acid deletions    or insertions, compared to the corresponding amino acid sequence    according to d);    and/or-   iii) the amino acid sequence according to e) and/or f) may be an    amino acid sequence that is derived from an amino acid sequence    according to d) by means of affinity maturation using one or more    techniques of affinity maturation known per se.

Also, similarly, when an amino acid sequence of the invention containsone or more amino acid sequences according to h) and/or i):

-   i) any amino acid substitution in such an amino acid sequence    according to h) and/or i) is preferably, and compared to the    corresponding amino acid sequence according to g), a conservative    amino acid substitution, (as defined herein);    and/or-   ii) the amino acid sequence according to h) and/or i) preferably    only contains amino acid substitutions, and no amino acid deletions    or insertions, compared to the corresponding amino acid sequence    according to g);    and/or-   iii) the amino acid sequence according to h) and/or i) may be an    amino acid sequence that is derived from an amino acid sequence    according to g) by means of affinity maturation using one or more    techniques of affinity maturation known per se.

It should be understood that the last preceding paragraphs alsogenerally apply to any amino acid sequences of the invention thatcomprise one or more amino acid sequences according to b), c), e), f),h) or i), respectively.

In this specific aspect, the amino acid sequence preferably comprisesone or more stretches of amino acid residues chosen from the groupconsisting of:

-   i) the amino acid sequences of SEQ ID NO's: 133 to 139;-   ii) the amino acid sequences of SEQ ID NO's: 147 to 153; and-   iii) the amino acid sequences of SEQ ID NO's: 161 to 167;    or any suitable combination thereof.

Also, preferably, in such an amino acid sequence, at least one of saidstretches of amino acid residues forms part of the antigen binding sitefor binding against OX40L.

In a more specific, but again non-limiting aspect, the invention relatesto an amino acid sequence directed against OX40L, that comprises two ormore stretches of amino acid residues chosen from the group consistingof:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;    such that (i) when the first stretch of amino acid residues    corresponds to one of the amino acid sequences according to a), b)    or c), the second stretch of amino acid residues corresponds to one    of the amino acid sequences according to d), e), f), g), h) or    i); (ii) when the first stretch of amino acid residues corresponds    to one of the amino acid sequences according to d), e) or f), the    second stretch of amino acid residues corresponds to one of the    amino acid sequences according to a), b), c), g), h) or i); or (iii)    when the first stretch of amino acid residues corresponds to one of    the amino acid sequences according to g), h) or i), the second    stretch of amino acid residues corresponds to one of the amino acid    sequences according to a), b), c), d), e) or f).

In this specific aspect, the amino acid sequence preferably comprisestwo or more stretches of amino acid residues chosen from the groupconsisting of:

-   i) the amino acid sequences of SEQ ID NO's: 133 to 139;-   ii) the amino acid sequences of SEQ ID NO's: 147 to 153; and-   iii) the amino acid sequences of SEQ ID NO's: 161 to 167;    such that, (i) when the first stretch of amino acid residues    corresponds to one of the amino acid sequences of SEQ ID NO's: 133    to 139, the second stretch of amino acid residues corresponds to one    of the amino acid sequences of SEQ ID NO's: 147 to 153 or of SEQ ID    NO's: 161 to 167; (ii) when the first stretch of amino acid residues    corresponds to one of the amino acid sequences of SEQ ID NO's: 147    to 153, the second stretch of amino acid residues corresponds to one    of the amino acid sequences of SEQ ID NO's: 133 to 139 or of SEQ ID    NO's: 161 to 167; or (iii) when the first stretch of amino acid    residues corresponds to one of the amino acid sequences of SEQ ID    NO's: 161 to 167, the second stretch of amino acid residues    corresponds to one of the amino acid sequences of SEQ ID NO's: 133    to 139 or of SEQ ID NO's: 147 to 153.

Also, in such an amino acid sequence, the at least two stretches ofamino acid residues again preferably form part of the antigen bindingsite for binding against OX40L.

In an even more specific, but non-limiting aspect, the invention relatesto an amino acid sequence directed against OX40L, that comprises threeor more stretches of amino acid residues, in which the first stretch ofamino acid residues is chosen from the group consisting of:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;    the second stretch of amino acid residues is chosen from the group    consisting of:-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;    and the third stretch of amino acid residues is chosen from the    group consisting of:-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167.

Preferably, in this specific aspect, the first stretch of amino acidresidues is chosen from the group consisting of the amino acid sequencesof SEQ ID NO's: 133 to 139; the second stretch of amino acid residues ischosen from the group consisting of the amino acid sequences of SEQ IDNO's: 147 to 153; and the third stretch of amino acid residues is chosenfrom the group consisting of the amino acid sequences of SEQ ID NO's:161 to 167.

Again, preferably, in such an amino acid sequence, the at least threestretches of amino acid residues forms part of the antigen binding sitefor binding against OX40L.

Preferred combinations of such stretches of amino acid sequences willbecome clear from the further disclosure herein.

Preferably, in such amino acid sequences the CDR sequences have at least70% amino acid identity, preferably at least 80% amino acid identity,more preferably at least 90% amino acid identity, such as 95% amino acididentity or more or even essentially 100% amino acid identity with theCDR sequences of at least one of the amino acid sequences of SEQ IDNO's: 179 to 185 (see Table A-1). This degree of amino acid identity canfor example be determined by determining the degree of amino acididentity (in a manner described herein) between said amino acid sequenceand one or more of the sequences of SEQ ID NO's: 179 to 185 (see TableA-1), in which the amino acid residues that form the framework regionsare disregarded. Also, such amino acid sequences of the invention can beas further described herein.

Also, such amino acid sequences are preferably such that they canspecifically bind (as defined herein) to OX40L; and more in particularbind to OX40L with an affinity (suitably measured and/or expressed as aK_(D)-value (actual or apparent), a K_(A)-value (actual or apparent), ak_(on)-rate and/or a k_(off)-rate, or alternatively as an IC₅₀ value, asfurther described herein) that is as defined herein.

When the amino acid sequence of the invention essentially consists of 4framework regions (FR1 to FR4, respectively) and 3 complementaritydetermining regions (CDR1 to CDR3, respectively), the amino acidsequence of the invention is preferably such that:

-   -   CDR1 is chosen from the group consisting of:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;

-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;

-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;    and/or    -   CDR2 is chosen from the group consisting of:

-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;

-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;

-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;    and/or    -   CDR3 is chosen from the group consisting of:

-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;

-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;

-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167.

In particular, such an amino acid sequence of the invention may be suchthat CDR1 is chosen from the group consisting of the amino acidsequences of SEQ ID NO's: 133 to 139; and/or CDR2 is chosen from thegroup consisting of the amino acid sequences of SEQ ID NO's: 147 to 153;and/or CDR3 is chosen from the group consisting of the amino acidsequences of SEQ ID NO's: 161 to 167.

In particular, when the amino acid sequence of the invention essentiallyconsists of 4 framework regions (FR1 to FR4, respectively) and 3complementarity determining regions (CDR1 to CDR3, respectively), theamino acid sequence of the invention is preferably such that:

-   -   CDR1 is chosen from the group consisting of:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;

-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;

-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;    and    -   CDR2 is chosen from the group consisting of:

-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;

-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;

-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;    and    -   CDR3 is chosen from the group consisting of:

-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;

-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;

-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167; or any suitable fragment of such an amino acid sequence

In particular, such an amino acid sequence of the invention may be suchthat CDR1 is chosen from the group consisting of the amino acidsequences of SEQ ID NO's: 133 to 139; and CDR2 is chosen from the groupconsisting of the amino acid sequences of SEQ ID NO's: 147 to 153; andCDR3 is chosen from the group consisting of the amino acid sequences ofSEQ ID NO's: 161 to 167.

Again, preferred combinations of CDR sequences will become clear fromthe further description herein.

Also, such amino acid sequences are preferably such that they canspecifically bind (as defined herein) to OX40L; and more in particularbind to OX40L with an affinity (suitably measured and/or expressed as aK_(D)-value (actual or apparent), a K_(A)-value (actual or apparent), ak_(on)-rate and/or a k_(off)-rate, or alternatively as an IC₅₀ value, asfurther described herein) that is as defined herein.

In one preferred, but non-limiting aspect, the invention relates to anamino acid sequence that essentially consists of 4 framework regions(FR1 to FR4, respectively) and 3 complementarity determining regions(CDR1 to CDR3, respectively), in which the CDR sequences of said aminoacid sequence have at least 70% amino acid identity, preferably at least80% amino acid identity, more preferably at least 90% amino acididentity, such as 95% amino acid identity or more or even essentially100% amino acid identity with the CDR sequences of at least one of theamino acid sequences of SEQ ID NO's: 179 to 185 (see Table A-1). Thisdegree of amino acid identity can for example be determined bydetermining the degree of amino acid identity (in a manner describedherein) between said amino acid sequence and one or more of thesequences of SEQ ID NO's: 179 to 185 (see Table A-1), in which the aminoacid residues that form the framework regions are disregarded. Suchamino acid sequences of the invention can be as further describedherein.

In such an amino acid sequence of the invention, the framework sequencesmay be any suitable framework sequences, and examples of suitableframework sequences will be clear to the skilled person, for example onthe basis the standard handbooks and the further disclosure and priorart mentioned herein.

The framework sequences are preferably (a suitable combination of)immunoglobulin framework sequences or framework sequences that have beenderived from immunoglobulin framework sequences (for example, byhumanization or camelization). For example, the framework sequences maybe framework sequences derived from a light chain variable domain (e.g.a V_(L)-sequence) and/or from a heavy chain variable domain (e.g. aV_(H)-sequence). In one particularly preferred aspect, the frameworksequences are either framework sequences that have been derived from aV_(HH)-sequence (in which said framework sequences may optionally havebeen partially or fully humanized) or are conventional V_(H) sequencesthat have been camelized (as defined herein).

The framework sequences are preferably such that the amino acid sequenceof the invention is a domain antibody (or an amino acid sequence that issuitable for use as a domain antibody); is a single domain antibody (oran amino acid sequence that is suitable for use as a single domainantibody); is a “dAb” (or an amino acid sequence that is suitable foruse as a dAb); or is a Nanobody (including but not limited to V_(HH)sequence). Again, suitable framework sequences will be clear to theskilled person, for example on the basis the standard handbooks and thefurther disclosure and prior art mentioned herein.

In particular, the framework sequences present in the amino acidsequences of the invention may contain one or more of Hallmark residues(as defined herein), such that the amino acid sequence of the inventionis a Nanobody. Some preferred, but non-limiting examples of (suitablecombinations of) such framework sequences will become clear from thefurther disclosure herein.

Again, as generally described herein for the amino acid sequences of theinvention, it is also possible to use suitable fragments (orcombinations of fragments) of any of the foregoing, such as fragmentsthat contain one or more CDR sequences, suitably flanked by and/orlinked via one or more framework sequences (for example, in the sameorder as these CDR's and framework sequences may occur in the full-sizedimmunoglobulin sequence from which the fragment has been derived). Suchfragments may also again be such that they comprise or can form animmunoglobulin fold, or alternatively be such that they do not compriseor cannot form an immunoglobulin fold.

In one specific aspect, such a fragment comprises a single CDR sequenceas described herein (and in particular a CDR3 sequence), that is flankedon each side by (part of) a framework sequence (and in particular, partof the framework sequence(s) that, in the immunoglobulin sequence fromwhich the fragment is derived, are adjacent to said CDR sequence. Forexample, a CDR3 sequence may be preceded by (part of) a FR3 sequence andfollowed by (part of) a FR4 sequence). Such a fragment may also containa disulphide bridge, and in particular a disulphide bridge that linksthe two framework regions that precede and follow the CDR sequence,respectively (for the purpose of forming such a disulphide bridge,cysteine residues that naturally occur in said framework regions may beused, or alternatively cysteine residues may be synthetically added toor introduced into said framework regions). For a further description ofthese “Expedite fragments”, reference is again made to WO 03/050531, aswell as to the US provisional application of Ablynx N.V. entitled“Peptides capable of binding to serum proteins” of Ablynx N.V.(inventors: Revets, Hilde Adi Pierrette; Kolkman, Joost Alexander; andHoogenboom, Hendricus Renerus Jacobus Mattheus) filed on Dec. 5, 2006(see also PCT/EP2007/063348).

In another aspect, the invention relates to a compound or construct, andin particular a protein or polypeptide (also referred to herein as a“compound of the invention” or “polypeptide of the invention”,respectively) that comprises or essentially consists of one or moreamino acid sequences of the invention (or suitable fragments thereof),and optionally further comprises one or more other groups, residues,moieties or binding units. As will become clear to the skilled personfrom the further disclosure herein, such further groups, residues,moieties, binding units or amino acid sequences may or may not providefurther functionality to the amino acid sequence of the invention(and/or to the compound or construct in which it is present) and may ormay not modify the properties of the amino acid sequence of theinvention.

For example, such further groups, residues, moieties or binding unitsmay be one or more additional amino acid sequences, such that thecompound or construct is a (fusion) protein or (fusion) polypeptide. Ina preferred but non-limiting aspect, said one or more other groups,residues, moieties or binding units are immunoglobulin sequences. Evenmore preferably, said one or more other groups, residues, moieties orbinding units are chosen from the group consisting of domain antibodies,amino acid sequences that are suitable for use as a domain antibody,single domain antibodies, amino acid sequences that are suitable for useas a single domain antibody, “dAb”'s, amino acid sequences that aresuitable for use as a dAb, or Nanobodies.

Alternatively, such groups, residues, moieties or binding units may forexample be chemical groups, residues, moieties, which may or may not bythemselves be biologically and/or pharmacologically active. For example,and without limitation, such groups may be linked to the one or moreamino acid sequences of the invention so as to provide a “derivative” ofan amino acid sequence or polypeptide of the invention, as furtherdescribed herein.

Also within the scope of the present invention are compounds orconstructs, that comprises or essentially consists of one or morederivatives as described herein, and optionally further comprises one ormore other groups, residues, moieties or binding units, optionallylinked via one or more linkers. Preferably, said one or more othergroups, residues, moieties or binding units are amino acid sequences.

In the compounds or constructs described above, the one or more aminoacid sequences of the invention and the one or more groups, residues,moieties or binding units may be linked directly to each other and/orvia one or more suitable linkers or spacers. For example, when the oneor more groups, residues, moieties or binding units are amino acidsequences, the linkers may also be amino acid sequences, so that theresulting compound or construct is a fusion (protein) or fusion(polypeptide).

As will be clear from the further description above and herein, thismeans that the amino acid sequences of the invention can be used as“building blocks” to form polypeptides of the invention, i.e. bysuitably combining them with other groups, residues, moieties or bindingunits, in order to form compounds or constructs as described herein(such as, without limitations, the biparatopic. bi/multivalent andbi/multispecific polypeptides of the invention described herein) whichcombine within one molecule one or more desired properties or biologicalfunctions.

The compounds or polypeptides of the invention can generally be preparedby a method which comprises at least one step of suitably linking theone or more amino acid sequences of the invention to the one or morefurther groups, residues, moieties or binding units, optionally via theone or more suitable linkers, so as to provide the compound orpolypeptide of the invention. Polypeptides of the invention can also beprepared by a method which generally comprises at least the steps ofproviding a nucleic acid that encodes a polypeptide of the invention,expressing said nucleic acid in a suitable manner, and recovering theexpressed polypeptide of the invention. Such methods can be performed ina manner known per se, which will be clear to the skilled person, forexample on the basis of the methods and techniques further describedherein.

The process of designing/selecting and/or preparing a compound orpolypeptide of the invention, starting from an amino acid sequence ofthe invention, is also referred to herein as “formatting” said aminoacid sequence of the invention; and an amino acid of the invention thatis made part of a compound or polypeptide of the invention is said to be“formatted” or to be “in the format of” said compound or polypeptide ofthe invention. Examples of ways in which an amino acid sequence of theinvention can be formatted and examples of such formats will be clear tothe skilled person based on the disclosure herein; and such formattedamino acid sequences form a further aspect of the invention.

In one specific aspect of the invention, a compound of the invention ora polypeptide of the invention may have an increased half-life, comparedto the corresponding amino acid sequence of the invention. Somepreferred, but non-limiting examples of such compounds and polypeptideswill become clear to the skilled person based on the further disclosureherein, and for example comprise amino acid sequences or polypeptides ofthe invention that have been chemically modified to increase thehalf-life thereof (for example, by means of pegylation); amino acidsequences of the invention that comprise at least one additional bindingsite for binding to a serum protein (such as serum albumin); orpolypeptides of the invention that comprise at least one amino acidsequence of the invention that is linked to at least one moiety (and inparticular at least one amino acid sequence) that increases thehalf-life of the amino acid sequence of the invention. Examples ofpolypeptides of the invention that comprise such half-life extendingmoieties or amino acid sequences will become clear to the skilled personbased on the further disclosure herein; and for example include, withoutlimitation, polypeptides in which the one or more amino acid sequencesof the invention are suitable linked to one or more serum proteins orfragments thereof (such as (human) serum albumin or suitable fragmentsthereof) or to one or more binding units that can bind to serum proteins(such as, for example, domain antibodies, amino acid sequences that aresuitable for use as a domain antibody, single domain antibodies, aminoacid sequences that are suitable for use as a single domain antibody,“dAb”'s, amino acid sequences that are suitable for use as a dAb, orNanobodies that can bind to serum proteins such as serum albumin (suchas human serum albumin), serum immunoglobulins such as IgG, ortransferrin; reference is made to the further description and referencesmentioned herein); polypeptides in which an amino acid sequence of theinvention is linked to an Fc portion (such as a human Fc) or a suitablepart or fragment thereof; or polypeptides in which the one or more aminoacid sequences of the invention are suitable linked to one or more smallproteins or peptides that can bind to serum proteins (such as, withoutlimitation, the proteins and peptides described in WO 91/01743, WO01/45746, WO 02/076489 and to the US provisional application of AblynxN.V. entitled “Peptides capable of binding to serum proteins” of AblynxN.V. filed on Dec. 5, 2006 (see also PCT/EP2007/063348).

Generally, the compounds or polypeptides of the invention with increasedhalf-life preferably have a half-life that is at least 1.5 times,preferably at least 2 times, such as at least 5 times, for example atleast 10 times or more than 20 times, greater than the half-life of thecorresponding amino acid sequence of the invention per se. For example,the compounds or polypeptides of the invention with increased half-lifemay have a half-life that is increased with more than 1 hours,preferably more than 2 hours, more preferably more than 6 hours, such asmore than 12 hours, or even more than 24, 48 or 72 hours, compared tothe corresponding amino acid sequence of the invention per se.

In a preferred, but non-limiting aspect of the invention, such compoundsor polypeptides of the invention have a serum half-life that isincreased with more than 1 hours, preferably more than 2 hours, morepreferably more than 6 hours, such as more than 12 hours, or even morethan 24, 48 or 72 hours, compared to the corresponding amino acidsequence of the invention per se.

In another preferred, but non-limiting aspect of the invention, suchcompounds or polypeptides of the invention exhibit a serum half-life inhuman of at least about 12 hours, preferably at least 24 hours, morepreferably at least 48 hours, even more preferably at least 72 hours ormore. For example, compounds or polypeptides of the invention may have ahalf-life of at least 5 days (such as about 5 to 10 days), preferably atleast 9 days (such as about 9 to 14 days), more preferably at leastabout 10 days (such as about 10 to 15 days), or at least about 11 days(such as about 11 to 16 days), more preferably at least about 12 days(such as about 12 to 18 days or more), or more than 14 days (such asabout 14 to 19 days).

In another aspect, the invention relates to a nucleic acid that encodesan amino acid sequence of the invention or a polypeptide of theinvention (or a suitable fragment thereof). Such a nucleic acid willalso be referred to herein as a “nucleic acid of the invention” and mayfor example be in the form of a genetic construct, as further describedherein.

In another aspect, the invention relates to a host or host cell thatexpresses (or that under suitable circumstances is capable ofexpressing) an amino acid sequence of the invention and/or a polypeptideof the invention; and/or that contains a nucleic acid of the invention.Some preferred but non-limiting examples of such hosts or host cellswill become clear from the further description herein.

The invention further relates to a product or composition containing orcomprising at least one amino acid sequence of the invention, at leastone polypeptide of the invention (or a suitable fragment thereof) and/orat least one nucleic acid of the invention, and optionally one or morefurther components of such compositions known per se, i.e. depending onthe intended use of the composition. Such a product or composition mayfor example be a pharmaceutical composition (as described herein), aveterinary composition or a product or composition for diagnostic use(as also described herein). Some preferred but non-limiting examples ofsuch products or compositions will become clear from the furtherdescription herein.

The invention also relates to the use of an amino acid sequence,Nanobody or polypeptide of the invention, or of a composition comprisingthe same, in (methods or compositions for) modulating OX40L, either invitro (e.g. in an in vitro or cellular assay) or in vivo (e.g. in an asingle cell or in a multicellular organism, and in particular in amammal, and more in particular in a human being, such as in a humanbeing that is at risk of or suffers from an inflammatory disorder suchas e.g. asthma and/or allergic asthma).

The invention also relates to methods for modulating OX40L, either invitro (e.g. in an in vitro or cellular assay) or in vivo (e.g. in an asingle cell or multicellular organism, and in particular in a mammal,and more in particular in a human being, such as in a human being thatis at risk of or suffers from an inflammatory disorder such as e.g.asthma and/or allergic asthma), which method comprises at least the stepof contacting OX40L with at least one amino acid sequence, Nanobody orpolypeptide of the invention, or with a composition comprising the same,in a manner and in an amount suitable to modulate OX40L with at leastone amino acid sequence, Nanobody or polypeptide of the invention.

The invention also relates to the use of an amino acid sequence,Nanobody or polypeptide of the invention in the preparation of acomposition (such as, without limitation, a pharmaceutical compositionor preparation as further described herein) for modulating OX40L, eitherin vitro (e.g. in an in vitro or cellular assay) or in vivo (e.g. in ana single cell or multicellular organism, and in particular in a mammal,and more in particular in a human being, such as in a human being thatis at risk of or suffers from an inflammatory disorder such as e.g.asthma and/or allergic asthma).

In the context of the present invention, “modulating” or “to modulate”generally means either reducing or inhibiting the activity of, oralternatively increasing the activity of OX40L, as measured using asuitable in vitro, cellular or in vivo assay (such as those mentionedherein). In particular, “modulating” or “to modulate” may mean eitherreducing or inhibiting the activity of, or alternatively increasing theactivity of OX40L, as measured using a suitable in vitro, cellular or invivo assay (such as those mentioned herein), by at least 1%, preferablyat least 5%, such as at least 10% or at least 25%, for example by atleast 50%, at least 60%, at least 70%, at least 80%, or 90% or more,compared to activity of OX40L in the same assay under the sameconditions but without the presence of the amino acid sequence, Nanobodyor polypeptide of the invention.

As will be clear to the skilled person, “modulating” may also involveeffecting a change (which may either be an increase or a decrease) inaffinity, avidity, specificity and/or selectivity of OX40L for one ormore of its targets, ligands or substrates; and/or effecting a change(which may either be an increase or a decrease) in the sensitivity ofOX40L for one or more conditions in the medium or surroundings in whichOX40L is present (such as pH, ion strength, the presence of co-factors,etc.), compared to the same conditions but without the presence of theamino acid sequence, Nanobody or polypeptide of the invention. As willbe clear to the skilled person, this may again be determined in anysuitable manner and/or using any suitable assay known per se, such asthe assays described herein or in the prior art cited herein.

“Modulating” may also mean effecting a change (i.e. an activity as anagonist or as an antagonist, respectively) with respect to one or morebiological or physiological mechanisms, effects, responses, functions,pathways or activities in which OX40L (or in which its substrate(s),ligand(s) or pathway(s) are involved, such as its signalling pathway ormetabolic pathway and their associated biological or physiologicaleffects) is involved. Again, as will be clear to the skilled person,such an action as an agonist or an antagonist may be determined in anysuitable manner and/or using any suitable (in vitro and usually cellularor in assay) assay known per se, such as the assays described herein orin the prior art cited herein. In particular, an action as an agonist orantagonist may be such that an intended biological or physiologicalactivity is increased or decreased, respectively, by at least 1%,preferably at least 5%, such as at least 10% or at least 25%, forexample by at least 50%, at least 60%, at least 70%, at least 80%, or90% or more, compared to the biological or physiological activity in thesame assay under the same conditions but without the presence of theamino acid sequence, Nanobody or polypeptide of the invention.

Modulating may for example involve reducing or inhibiting the binding ofOX40L to one of its substrates or ligands and/or competing with anatural ligand, substrate for binding to OX40L. Modulating may alsoinvolve activating OX40L or the mechanism or pathway in which it isinvolved. Modulating may be reversible or irreversible, but forpharmaceutical and pharmacological purposes will usually be in areversible manner.

The invention further relates to methods for preparing or generating theamino acid sequences, polypeptides, nucleic acids, host cells, productsand compositions described herein. Some preferred but non-limitingexamples of such methods will become clear from the further descriptionherein.

Generally, these methods may comprise the steps of:

-   a) providing a set, collection or library of amino acid sequences;    and-   b) screening said set, collection or library of amino acid sequences    for amino acid sequences that can bind to and/or have affinity for    OX40L;    and-   c) isolating the amino acid sequence(s) that can bind to and/or have    affinity for OX40L.

In such a method, the set, collection or library of amino acid sequencesmay be any suitable set, collection or library of amino acid sequences.For example, the set, collection or library of amino acid sequences maybe a set, collection or library of immunoglobulin sequences (asdescribed herein), such as a naïve set, collection or library ofimmunoglobulin sequences; a synthetic or semi-synthetic set, collectionor library of immunoglobulin sequences; and/or a set, collection orlibrary of immunoglobulin sequences that have been subjected to affinitymaturation.

Also, in such a method, the set, collection or library of amino acidsequences may be a set, collection or library of heavy chain variabledomains (such as V_(H) domains or V_(HH) domains) or of light chainvariable domains. For example, the set, collection or library of aminoacid sequences may be a set, collection or library of domain antibodiesor single domain antibodies, or may be a set, collection or library ofamino acid sequences that are capable of functioning as a domainantibody or single domain antibody.

In a preferred aspect of this method, the set, collection or library ofamino acid sequences may be an immune set, collection or library ofimmunoglobulin sequences, for example derived from a mammal that hasbeen suitably immunized with OX40L or with a suitable antigenicdeterminant based thereon or derived therefrom, such as an antigenicpart, fragment, region, domain, loop or other epitope thereof. In oneparticular aspect, said antigenic determinant may be an extracellularpart, region, domain, loop or other extracellular epitope(s).

In the above methods, the set, collection or library of amino acidsequences may be displayed on a phage, phagemid, ribosome or suitablemicro-organism (such as yeast), such as to facilitate screening.Suitable methods, techniques and host organisms for displaying andscreening (a set, collection or library of) amino acid sequences will beclear to the person skilled in the art, for example on the basis of thefurther disclosure herein. Reference is also made to the review byHoogenboom in Nature Biotechnology, 23, 9, 1105-1116 (2005).

In another aspect, the method for generating amino acid sequencescomprises at least the steps of:

-   a) providing a collection or sample of cells expressing amino acid    sequences;-   b) screening said collection or sample of cells for cells that    express an amino acid sequence that can bind to and/or has affinity    for OX40L;    and-   c) either (i) isolating said amino acid sequence; or (ii) isolating    from said cell a nucleic acid sequence that encodes said amino acid    sequence, followed by expressing said amino acid sequence.

For example, when the desired amino acid sequence is an immunoglobulinsequence, the collection or sample of cells may for example be acollection or sample of B-cells. Also, in this method, the sample ofcells may be derived from a mammal that has been suitably immunized withOX40L or with a suitable antigenic determinant based thereon or derivedtherefrom, such as an antigenic part, fragment, region, domain, loop orother epitope thereof. In one particular aspect, said antigenicdeterminant may be an extracellular part, region, domain, loop or otherextracellular epitope(s).

The above method may be performed in any suitable manner, as will beclear to the skilled person. Reference is for example made to EP 0 542810, WO 05/19824, WO 04/051268 and WO 04/106377. The screening of stepb) is preferably performed using a flow cytometry technique such asFACS. For this, reference is for example made to Lieby et al., Blood,Vol. 97, No. 12, 3820 (2001).

In another aspect, the method for generating an amino acid sequencedirected against OX40L may comprise at least the steps of:

-   a) providing a set, collection or library of nucleic acid sequences    encoding amino acid sequences;-   b) screening said set, collection or library of nucleic acid    sequences for nucleic acid sequences that encode an amino acid    sequence that can bind to and/or has affinity for OX40L;    and-   c) isolating said nucleic acid sequence, followed by expressing said    amino acid sequence.

In such a method, the set, collection or library of nucleic acidsequences encoding amino acid sequences may for example be a set,collection or library of nucleic acid sequences encoding a naïve set,collection or library of immunoglobulin sequences; a set, collection orlibrary of nucleic acid sequences encoding a synthetic or semi-syntheticset, collection or library of immunoglobulin sequences; and/or a set,collection or library of nucleic acid sequences encoding a set,collection or library of immunoglobulin sequences that have beensubjected to affinity maturation.

Also, in such a method, the set, collection or library of nucleic acidsequences may encode a set, collection or library of heavy chainvariable domains (such as V_(H) domains or V_(HH) domains) or of lightchain variable domains. For example, the set, collection or library ofnucleic acid sequences may encode a set, collection or library of domainantibodies or single domain antibodies, or a set, collection or libraryof amino acid sequences that are capable of functioning as a domainantibody or single domain antibody.

In a preferred aspect of this method, the set, collection or library ofnucleic acid sequences may be an immune set, collection or library ofnucleic acid sequences, for example derived from a mammal that has beensuitably immunized with OX40L or with a suitable antigenic determinantbased thereon or derived therefrom, such as an antigenic part, fragment,region, domain, loop or other epitope thereof. In one particular aspect,said antigenic determinant may be an extracellular part, region, domain,loop or other extracellular epitope(s).

The set, collection or library of nucleic acid sequences may for exampleencode an immune set, collection or library of heavy chain variabledomains or of light chain variable domains. In one specific aspect, theset, collection or library of nucleotide sequences may encode a set,collection or library of V_(HH) sequences.

In the above methods, the set, collection or library of nucleotidesequences may be displayed on a phage, phagemid, ribosome or suitablemicro-organism (such as yeast), such as to facilitate screening.Suitable methods, techniques and host organisms for displaying andscreening (a set, collection or library of) nucleotide sequencesencoding amino acid sequences will be clear to the person skilled in theart, for example on the basis of the further disclosure herein.Reference is also made to the review by Hoogenboom in NatureBiotechnology, 23, 9, 1105-1116 (2005).

In another aspect, the method for generating an amino acid sequencedirected against OX40L may comprise at least the steps of:

-   a) providing a set, collection or library of nucleic acid sequences    encoding amino acid sequences;-   b) screening said set, collection or library of nucleic acid    sequences for nucleic acid sequences that encode an amino acid    sequence that can bind to and/or has affinity for OX40L and that is    cross-blocked or is cross blocking a Nanobody of the invention, e.g.    one of SEQ ID NO's: 179 to 185 (Table A-1), or a humanized or    sequence optimized Nanobody of the invention such as e.g. one of SEQ    ID NO's: 199 to 226 (Table A-2), or a polypeptide or construct of    the invention, e.g. one of SEQ ID NO's: 186 to 198 and 227 to 234    (see Table A-3 and Table A-4); and-   c) isolating said nucleic acid sequence, followed by expressing said    amino acid sequence.

The invention also relates to amino acid sequences that are obtained bythe above methods, or alternatively by a method that comprises the oneof the above methods and in addition at least the steps of determiningthe nucleotide sequence or amino acid sequence of said immunoglobulinsequence; and of expressing or synthesizing said amino acid sequence ina manner known per se, such as by expression in a suitable host cell orhost organism or by chemical synthesis.

Also, following the steps above, one or more amino acid sequences of theinvention may be suitably humanized (or alternatively camelized); and/orthe amino acid sequence(s) thus obtained may be linked to each other orto one or more other suitable amino acid sequences (optionally via oneor more suitable linkers) so as to provide a polypeptide of theinvention. Also, a nucleic acid sequence encoding an amino acid sequenceof the invention may be suitably humanized (or alternatively camelized)and suitably expressed; and/or one or more nucleic acid sequencesencoding an amino acid sequence of the invention may be linked to eachother or to one or more nucleic acid sequences that encode othersuitable amino acid sequences (optionally via nucleotide sequences thatencode one or more suitable linkers), after which the nucleotidesequence thus obtained may be suitably expressed so as to provide apolypeptide of the invention.

The invention further relates to applications and uses of the amino acidsequences, compounds, constructs, polypeptides, nucleic acids, hostcells, products and compositions described herein, as well as to methodsfor the prevention and/or treatment for diseases and disordersassociated with OX40L. Some preferred but non-limiting applications anduses will become clear from the further description herein.

The invention also relates to the amino acid sequences, compounds,constructs, polypeptides, nucleic acids, host cells, products andcompositions described herein for use in therapy.

In particular, the invention also relates to the amino acid sequences,compounds, constructs, polypeptides, nucleic acids, host cells, productsand compositions described herein for use in therapy of a disease ordisorder that can be prevented or treated by administering, to a subjectin need thereof, of (a pharmaceutically effective amount of) an aminoacid sequence, compound, construct or polypeptide as described herein.

More in particular, the invention relates to the amino acid sequences,compounds, constructs, polypeptides, nucleic acids, host cells, productsand compositions described herein for use in therapy of inflammatorydisorders such as e.g. asthma and/or allergic asthma.

Other aspects, embodiments, advantages and applications of the inventionwill also become clear from the further description herein, in which theinvention will be described and discussed in more detail with referenceto the Nanobodies of the invention and polypeptides of the inventioncomprising the same, which form some of the preferred aspects of theinvention.

As will become clear from the further description herein, Nanobodiesgenerally offer certain advantages (outlined herein) compared to “dAb's”or similar (single) domain antibodies or immunoglobulin sequences, whichadvantages are also provided by the Nanobodies of the invention.However, it will be clear to the skilled person that the more generalaspects of the teaching below can also be applied (either directly oranalogously) to other amino acid sequences of the invention.

DESCRIPTION OF THE FIGURES

FIG. 1: Specificity of OX40L blocking Nanobody OX40L01E07. Binding ofthe OX40L01E07 to hOX40L captured on neutravidin was only inhibited byexogenously added hOX40L (o, dashed line) and was not affected by theaddition of the other TNF superfamily members, i.e. hRANKL (▪), hCD30L(▴), hCD40L (▾), hTRAIL (^(••)) or hTNFa (•).

FIGS. 2A-2B: Inhibition of OX40L mediated effector memory T-cellactivation by monovalent and trivalent bispecific anti-OX40L Nanobodies.2×10⁵ CD45RA− CCR7-effector memory T-cells, 1×10⁴ hOX40L expressing CHOcells and dilution series of anti-OX40L Nanobodies or anti-OX40Lbenchmark were incubated for 3 days at 37° C. IL-4 production wasmeasured in ELISA. All monovalent Nanobodies and benchmark Fab are shownwith dotted lines and open symbols: OX40L01E07 (□), OX40L18E09 (∘) andOX40L19D08 (⁻) in FIG. 2A; OX40L01E10 (□), OX40L15B07 (∘), OX40L01B11(⁻) in FIG. 2B, benchmark Fab (r). All trivalent bispecific Nanobodiesand the benchmark IgG are shown with solid lines and symbols: OX40L003(▪), OX40L004 (•) and OX40L005 (♦) in FIG. 2A; OX40L006 (▪), OX40L007(•) and OX40L009 (^(••)) in FIG. 2B, benchmark IgG (▴).

DETAILED DESCRIPTION OF THE INVENTION

In the present description, examples and claims:

-   a) Unless indicated or defined otherwise, all terms used have their    usual meaning in the art, which will be clear to the skilled person.    Reference is for example made to the standard handbooks mentioned in    paragraph a) on page 46 of WO 08/020079.-   b) Unless indicated otherwise, the terms “immunoglobulin sequence”,    “sequence”, “nucleotide sequence” and “nucleic acid” are as    described in paragraph b) on page 46 of WO 08/020079.-   c) Unless indicated otherwise, all methods, steps, techniques and    manipulations that are not specifically described in detail can be    performed and have been performed in a manner known per se, as will    be clear to the skilled person. Reference is for example again made    to the standard handbooks and the general background art mentioned    herein and to the further references cited therein; as well as to    for example the following reviews Presta, Adv. Drug Deliv. Rev.    2006, 58 (5-6): 640-56; Levin and Weiss, Mol. Biosyst. 2006, 2(1):    49-57; Irving et al., J. Immunol. Methods, 2001, 248 (1-2), 31-45;    Schmitz et al., Placenta, 2000, 21 Suppl. A, S106-12, Gonzales et    al., Tumour Biol., 2005, 26(1), 31-43, which describe techniques for    protein engineering, such as affinity maturation and other    techniques for improving the specificity and other desired    properties of proteins such as immunoglobulins.-   d) Amino acid residues will be indicated according to the standard    three-letter or one-letter amino acid code. Reference is made to    Table A-2 on page 48 of the International application WO 08/020079    of Ablynx N.V. entitled “Amino acid sequences directed against IL-6R    and polypeptides comprising the same for the treatment of diseases    and disorders associated with Il-6 mediated signalling”.-   e) For the purposes of comparing two or more nucleotide sequences,    the percentage of “sequence identity” between a first nucleotide    sequence and a second nucleotide sequence may be calculated or    determined as described in paragraph e) on page 49 of WO 08/020079    (incorporated herein by reference), such as by dividing [the number    of nucleotides in the first nucleotide sequence that are identical    to the nucleotides at the corresponding positions in the second    nucleotide sequence] by [the total number of nucleotides in the    first nucleotide sequence] and multiplying by [100%], in which each    deletion, insertion, substitution or addition of a nucleotide in the    second nucleotide sequence—compared to the first nucleotide    sequence—is considered as a difference at a single nucleotide    (position); or using a suitable computer algorithm or technique,    again as described in paragraph e) on pages 49 of WO 08/020079    (incorporated herein by reference).-   f) For the purposes of comparing two or more amino acid sequences,    the percentage of “sequence identity” between a first amino acid    sequence and a second amino acid sequence (also referred to herein    as “amino acid identity”) may be calculated or determined as    described in paragraph f) on pages 49 and 50 of WO 08/020079    (incorporated herein by reference), such as by dividing [the number    of amino acid residues in the first amino acid sequence that are    identical to the amino acid residues at the corresponding positions    in the second amino acid sequence] by [the total number of amino    acid residues in the first amino acid sequence] and multiplying by    [100%], in which each deletion, insertion, substitution or addition    of an amino acid residue in the second amino acid sequence—compared    to the first amino acid sequence—is considered as a difference at a    single amino acid residue (position), i.e. as an “amino acid    difference” as defined herein; or using a suitable computer    algorithm or technique, again as described in paragraph f) on pages    49 and 50 of WO 08/020079 (incorporated herein by reference).    -   Also, in determining the degree of sequence identity between two        amino acid sequences, the skilled person may take into account        so-called “conservative” amino acid substitutions, as described        on page 50 of WO 08/020079.    -   Any amino acid substitutions applied to the polypeptides        described herein may also be based on the analysis of the        frequencies of amino acid variations between homologous proteins        of different species developed by Schulz et al., Principles of        Protein Structure, Springer-Verlag, 1978, on the analyses of        structure forming potentials developed by Chou and Fasman,        Biochemistry 13: 211, 1974 and Adv. Enzymol., 47: 45-149, 1978,        and on the analysis of hydrophobicity patterns in proteins        developed by Eisenberg et al., Proc. Natl. Acad. Sci. USA 81:        140-144, 1984; Kyte & Doolittle; J Molec. Biol. 157: 105-132,        198 1, and Goldman et al., Ann. Rev. Biophys. Chem. 15: 321-353,        1986, all incorporated herein in their entirety by reference.        Information on the primary, secondary and tertiary structure of        Nanobodies is given in the description herein and in the general        background art cited above. Also, for this purpose, the crystal        structure of a V_(HH) domain from a llama is for example given        by Desmyter et al., Nature Structural Biology, Vol. 3, 9, 803        (1996); Spinelli et al., Natural Structural Biology (1996); 3,        752-757; and Decanniere et al., Structure, Vol. 7, 4, 361        (1999). Further information about some of the amino acid        residues that in conventional V_(H) domains form the V_(H)/V_(L)        interface and potential camelizing substitutions on these        positions can be found in the prior art cited above.-   g) Amino acid sequences and nucleic acid sequences are said to be    “exactly the same” if they have 100% sequence identity (as defined    herein) over their entire length.-   h) When comparing two amino acid sequences, the term “amino acid    difference” refers to an insertion, deletion or substitution of a    single amino acid residue on a position of the first sequence,    compared to the second sequence; it being understood that two amino    acid sequences can contain one, two or more such amino acid    differences.-   i) When a nucleotide sequence or amino acid sequence is said to    “comprise” another nucleotide sequence or amino acid sequence,    respectively, or to “essentially consist of” another nucleotide    sequence or amino acid sequence, this has the meaning given in    paragraph i) on pages 51-52 of WO 08/020079.-   j) The term “in essentially isolated form” has the meaning given to    it in paragraph j) on pages 52 and 53 of WO 08/020079.-   k) The terms “domain” and “binding domain” have the meanings given    to it in paragraph k) on page 53 of WO 08/020079.-   l) The term “variable domain” refers to the part or domain of an    immunoglobulin molecule or antibody which is partially or fully    responsible for antigen binding.-   m) The term “single variable domain” or “immunoglobulin single    variable domain”, defines molecules wherein the antigen binding site    is present on, and formed by, a single immunoglobulin domain. This    sets single variable domains apart from “conventional”    immunoglobulins or their fragments, wherein two immunoglobulin    domains, in particular two “variable domains” interact to form an    antigen binding site. Typically, in conventional immunoglobulins, a    heavy chain variable domain (VH) and a light chain variable domain    (VL) interact to form an antigen binding site. In this case, the    complementarity determining regions (CDRs) of both VH and VL will    contribute to the antigen binding site, i.e. a total of 6 CDRs will    be involved in antigen binding site formation.    -   In contrast, the binding site of an immunoglobulin single        variable domain is formed by a single VH or VL domain. Hence,        the antigen binding site of an immunoglobulin single variable        domain is formed by no more than three CDRs. The term        “immunoglobulin single variable domain” does comprise fragments        of conventional immunoglobulins wherein the antigen binding site        is formed by a single variable domain.    -   Generally, immunoglobulin single variable domains will be amino        acid sequences that essentially consist of 4 framework regions        (FR1 to FR4 respectively) and 3 complementarity determining        regions (CDR1 to CDR3 respectively); or any suitable fragment of        such an amino acid sequence (which will then usually contain at        least some of the amino acid residues that form at least one of        the CDR's). Such immunoglobulin single variable domains and        fragments are most preferably such that they comprise an        immunoglobulin fold or are capable for forming, under suitable        conditions, an immunoglobulin fold. As such, the immunoglobulin        single variable domain may for example comprise a light chain        variable domain sequence (e.g. a V_(L)-sequence) or a suitable        fragment thereof; or a heavy chain variable domain sequence        (e.g. a V_(H)-sequence or V_(HH) sequence) or a suitable        fragment thereof; as long as it is capable of forming a single        antigen binding unit (i.e. a functional antigen binding unit        that essentially consists of the immunoglobulin single variable        domain, such that the single antigen binding domain does not        need to interact with another variable domain to form a        functional antigen binding unit, as is for example the case for        the variable domains that are present in for example        conventional antibodies and scFv fragments that need to interact        with another variable domain—e.g. through a V_(H)/V_(L)        interaction—to form a functional antigen binding domain).    -   In one aspect of the invention, the immunoglobulin single        variable domains are light chain variable domain sequences (e.g.        a V_(L)-sequence), or heavy chain variable domain sequences        (e.g. a V_(H)-sequence); more specifically, the single variable        domains can be heavy chain variable domain sequences that are        derived from a conventional four-chain antibody or heavy chain        variable domain sequences that are derived from a heavy chain        antibody.    -   The immunoglobulin single variable domain may be a domain        antibody (or an amino acid sequence that is suitable for use as        a domain antibody), a single domain antibody (or an amino acid        sequence that is suitable for use as a single domain antibody),        a “dAb” (or an amino acid sequence that is suitable for use as a        dAb) or a Nanobody® (as defined herein, and including but not        limited to a V_(HH) sequence) [Note: Nanobody® and Nanobodies®        are registered trademarks of Ablynx N.V.]; other immunoglobulin        single variable domains, or any suitable fragment of any one        thereof. For a general description of (single) domain        antibodies, reference is also made to the prior art cited        herein, as well as to EP 0 368 684. For the term “dAb's”,        reference is for example made to Ward et al. 1989 (Nature 341:        544-546), to Holt et al. 2003 (Trends Biotechnol. 21: 484-490);        as well as to for example WO 04/068820, WO 06/030220, WO        06/003388 and other published patent applications of Domantis        Ltd. It should also be noted that, although less preferred in        the context of the present invention because they are not of        mammalian origin, immunoglobulin single variable domains can be        derived from certain species of shark (for example, the        so-called “IgNAR domains”, see for example WO 05/18629).-   n) The terms “antigenic determinant” and “epitope”, which may also    be used interchangeably herein, have the meanings given to it in    paragraph I) on page 53 of WO 08/020079.-   o) As further described in paragraph m) on page 53 of WO 08/020079,    an amino acid sequence (such as a Nanobody, an antibody, a    polypeptide of the invention, or generally an antigen binding    protein or polypeptide or a fragment thereof) that can    (specifically) bind to, that has affinity for and/or that has    specificity for a specific antigenic determinant, epitope, antigen    or protein (or for at least one part, fragment or epitope thereof)    is said to be “against” or “directed against” said antigenic    determinant, epitope, antigen or protein.-   p) The term “specificity” has the meaning given to it in    paragraph n) on pages 53-56 of WO 08/020079; and as mentioned    therein refers to the number of different types of antigens or    antigenic determinants to which a particular antigen-binding    molecule or antigen-binding protein (such as a Nanobody or a    polypeptide of the invention) molecule can bind. The specificity of    an antigen-binding protein can be determined based on affinity    and/or avidity, as described on pages 53-56 of WO 08/020079    (incorporated herein by reference), which also describes some    preferred techniques for measuring binding between an    antigen-binding molecule (such as a Nanobody or polypeptide of the    invention) and the pertinent antigen. Typically, antigen-binding    proteins (such as the amino acid sequences, Nanobodies and/or    polypeptides of the invention) will bind to their antigen with a    dissociation constant (K_(D)) of 10⁻⁵ to 10⁻¹² moles/liter or less,    and preferably 10⁻⁷ to 10⁻¹² moles/liter or less and more preferably    10⁻⁸ to 10⁻¹² moles/liter (i.e. with an association constant (K_(A))    of 10⁵ to 10¹² liter/moles or more, and preferably 10⁷ to 10¹²    liter/moles or more and more preferably 10⁸ to 10¹² liter/moles).    Any K_(D) value greater than 10⁴ mol/liter (or any K_(A) value lower    than 10⁴ M⁻¹) liters/mol is generally considered to indicate    non-specific binding. Preferably, a monovalent immunoglobulin    sequence of the invention will bind to the desired antigen with an    affinity less than 500 nM, preferably less than 200 nM, more    preferably less than 10 nM, such as less than 500 pM. Specific    binding of an antigen-binding protein to an antigen or antigenic    determinant can be determined in any suitable manner known per se,    including, for example, Scatchard analysis and/or competitive    binding assays, such as radioimmunoassays (RIA), enzyme immunoassays    (EIA) and sandwich competition assays, and the different variants    thereof known per se in the art; as well as the other techniques    mentioned herein. As will be clear to the skilled person, and as    described on pages 53-56 of WO 08/020079, the dissociation constant    may be the actual or apparent dissociation constant. Methods for    determining the dissociation constant will be clear to the skilled    person, and for example include the techniques mentioned on pages    53-56 of WO 08/020079.-   q) The half-life of an amino acid sequence, compound or polypeptide    of the invention can generally be defined as described in    paragraph o) on page 57 of WO 08/020079 and as mentioned therein    refers to the time taken for the serum concentration of the amino    acid sequence, compound or polypeptide to be reduced by 50%, in    vivo, for example due to degradation of the sequence or compound    and/or clearance or sequestration of the sequence or compound by    natural mechanisms. The in vivo half-life of an amino acid sequence,    compound or polypeptide of the invention can be determined in any    manner known per se, such as by pharmacokinetic analysis. Suitable    techniques will be clear to the person skilled in the art, and may    for example generally be as described in paragraph o) on page 57 of    WO 08/020079. As also mentioned in paragraph o) on page 57 of WO    08/020079, the half-life can be expressed using parameters such as    the t½-alpha, t½-beta and the area under the curve (AUC). Reference    is for example made to the Experimental Part below, as well as to    the standard handbooks, such as Kenneth, A et al: Chemical Stability    of Pharmaceuticals: A Handbook for Pharmacists and Peters et al,    Pharmacokinete analysis: A Practical Approach (1996). Reference is    also made to “Pharmacokinetics”, M Gibaldi & D Perron, published by    Marcel Dekker, 2nd Rev. edition (1982). The terms “increase in    half-life” or “increased half-life” as also as defined in    paragraph o) on page 57 of WO 08/020079 and in particular refer to    an increase in the t½-beta, either with or without an increase in    the t½-alpha and/or the AUC or both.-   r) In the context of the present invention, “modulating” or “to    modulate” generally means either reducing or inhibiting the activity    of, or alternatively increasing the activity of, a target or    antigen, as measured using a suitable in vitro, cellular or in vivo    assay. In particular, “modulating” or “to modulate” may mean either    reducing or inhibiting the activity of, or alternatively increasing    a (relevant or intended) biological activity of, a target or    antigen, as measured using a suitable in vitro, cellular or in vivo    assay (which will usually depend on the target or antigen involved),    by at least 1%, preferably at least 5%, such as at least 10% or at    least 25%, for example by at least 50%, at least 60%, at least 70%,    at least 80%, or 90% or more, compared to activity of the target or    antigen in the same assay under the same conditions but without the    presence of the construct of the invention.    -   As will be clear to the skilled person, “modulating” may also        involve effecting a change (which may either be an increase or a        decrease) in affinity, avidity, specificity and/or selectivity        of a target or antigen for one or more of its ligands, binding        partners, partners for association into a homomultimeric or        heteromultimeric form, or substrates; and/or effecting a change        (which may either be an increase or a decrease) in the        sensitivity of the target or antigen for one or more conditions        in the medium or surroundings in which the target or antigen is        present (such as pH, ion strength, the presence of co-factors,        etc.), compared to the same conditions but without the presence        of the construct of the invention. As will be clear to the        skilled person, this may again be determined in any suitable        manner and/or using any suitable assay known per se, depending        on the target or antigen involved.    -   “Modulating” may also mean effecting a change (i.e. an activity        as an agonist, as an antagonist or as a reverse agonist,        respectively, depending on the target or antigen and the desired        biological or physiological effect) with respect to one or more        biological or physiological mechanisms, effects, responses,        functions, pathways or activities in which the target or antigen        (or in which its substrate(s), ligand(s) or pathway(s) are        involved, such as its signalling pathway or metabolic pathway        and their associated biological or physiological effects) is        involved. Again, as will be clear to the skilled person, such an        action as an agonist or an antagonist may be determined in any        suitable manner and/or using any suitable (in vitro and usually        cellular or in assay) assay known per se, depending on the        target or antigen involved. In particular, an action as an        agonist or antagonist may be such that an intended biological or        physiological activity is increased or decreased, respectively,        by at least 1%, preferably at least 5%, such as at least 10% or        at least 25%, for example by at least 50%, at least 60%, at        least 70%, at least 80%, or 90% or more, compared to the        biological or physiological activity in the same assay under the        same conditions but without the presence of the construct of the        invention.    -   Modulating may for example also involve allosteric modulation of        the target or antigen; and/or reducing or inhibiting the binding        of the target or antigen to one of its substrates or ligands        and/or competing with a natural ligand, substrate for binding to        the target or antigen. Modulating may also involve activating        the target or antigen or the mechanism or pathway in which it is        involved. Modulating may for example also involve effecting a        change in respect of the folding or confirmation of the target        or antigen, or in respect of the ability of the target or        antigen to fold, to change its confirmation (for example, upon        binding of a ligand), to associate with other (sub)units, or to        disassociate. Modulating may for example also involve effecting        a change in the ability of the target or antigen to transport        other compounds or to serve as a channel for other compounds        (such as ions).    -   Modulating may be reversible or irreversible, but for        pharmaceutical and pharmacological purposes will usually be in a        reversible manner.-   s) In respect of a target or antigen, the term “interaction site” on    the target or antigen means a site, epitope, antigenic determinant,    part, domain or stretch of amino acid residues on the target or    antigen that is a site for binding to a ligand, receptor or other    binding partner, a catalytic site, a cleavage site, a site for    allosteric interaction, a site involved in multimerisation (such as    homomerization or heterodimerization) of the target or antigen; or    any other site, epitope, antigenic determinant, part, domain or    stretch of amino acid residues on the target or antigen that is    involved in a biological action or mechanism of the target or    antigen. More generally, an “interaction site” can be any site,    epitope, antigenic determinant, part, domain or stretch of amino    acid residues on the target or antigen to which an amino acid    sequence or polypeptide of the invention can bind such that the    target or antigen (and/or any pathway, interaction, signalling,    biological mechanism or biological effect in which the target or    antigen is involved) is modulated (as defined herein).-   t) An amino acid sequence or polypeptide is said to be “specific    for” a first target or antigen compared to a second target or    antigen when is binds to the first antigen with an affinity (as    described above, and suitably expressed as a K_(D) value, K_(A)    value, K_(off) rate and/or K_(on) rate) that is at least 10 times,    such as at least 100 times, and preferably at least 1000 times, and    up to 10.000 times or more better than the affinity with which said    amino acid sequence or polypeptide binds to the second target or    polypeptide. For example, the first antigen may bind to the target    or antigen with a K_(D) value that is at least 10 times less, such    as at least 100 times less, and preferably at least 1000 times less,    such as 10.000 times less or even less than that, than the K_(D)    with which said amino acid sequence or polypeptide binds to the    second target or polypeptide. Preferably, when an amino acid    sequence or polypeptide is “specific for” a first target or antigen    compared to a second target or antigen, it is directed against (as    defined herein) said first target or antigen, but not directed    against said second target or antigen.-   u) The terms “cross-block”, “cross-blocked” and “cross-blocking” are    used interchangeably herein to mean the ability of an amino acid    sequence or other binding agents (such as a Nanobody, polypeptide or    compound or construct of the invention) to interfere with the    binding of other amino acid sequences or binding agents of the    invention to a given target. The extend to which an amino acid    sequence or other binding agents of the invention is able to    interfere with the binding of another to the target, and therefore    whether it can be said to cross-block according to the invention,    can be determined using competition binding assays. One particularly    suitable quantitative cross-blocking assay uses a Biacore machine    which can measure the extent of interactions using surface plasmon    resonance technology. Another suitable quantitative cross-blocking    assay uses an ELISA-based approach to measure competition between    amino acid sequences or other binding agents in terms of their    binding to the target.    -   The following generally describes a suitable Biacore assay for        determining whether an amino acid sequence or other binding        agent cross-blocks or is capable of cross-blocking according to        the invention. It will be appreciated that the assay can be used        with any of the amino acid sequences or other binding agents        described herein. The Biacore machine (for example the        Biacore 3000) is operated in line with the manufacturer's        recommendations. Thus in one cross-blocking assay, the target        protein is coupled to a CM5 Biacore chip using standard amine        coupling chemistry to generate a surface that is coated with the        target. Typically 200-800 resonance units of the target would be        coupled to the chip (an amount that gives easily measurable        levels of binding but that is readily saturable by the        concentrations of test reagent being used). Two test amino acid        sequences (termed A* and B*) to be assessed for their ability to        cross-block each other are mixed at a one to one molar ratio of        binding sites in a suitable buffer to create the test mixture.        When calculating the concentrations on a binding site basis the        molecular weight of an amino acid sequence is assumed to be the        total molecular weight of the amino acid sequence divided by the        number of target binding sites on that amino acid sequence. The        concentration of each amino acid sequence in the test mix should        be high enough to readily saturate the binding sites for that        amino acid sequence on the target molecules captured on the        Biacore chip. The amino acid sequences in the mixture are at the        same molar concentration (on a binding basis) and that        concentration would typically be between 1.00 and 1.5 micromolar        (on a binding site basis). Separate solutions containing A*        alone and B* alone are also prepared. A* and B* in these        solutions should be in the same buffer and at the same        concentration as in the test mix. The test mixture is passed        over the target-coated Biacore chip and the total amount of        binding recorded. The chip is then treated in such a way as to        remove the bound amino acid sequences without damaging the        chip-bound target. Typically this is done by treating the chip        with 30 mM HCl for 60 seconds. The solution of A* alone is then        passed over the target-coated surface and the amount of binding        recorded. The chip is again treated to remove all of the bound        amino acid sequences without damaging the chip-bound target. The        solution of B* alone is then passed over the target-coated        surface and the amount of binding recorded. The maximum        theoretical binding of the mixture of A* and B* is next        calculated, and is the sum of the binding of each amino acid        sequence when passed over the target surface alone. If the        actual recorded binding of the mixture is less than this        theoretical maximum then the two amino acid sequences are        cross-blocking each other. Thus, in general, a cross-blocking        amino acid sequence or other binding agent according to the        invention is one which will bind to the target in the above        Biacore cross-blocking assay such that, during the assay and in        the presence of a second amino acid sequence or other binding        agent of the invention, the recorded binding is between 80% and        0.1% (e.g. 80% to 4%) of the maximum theoretical binding,        specifically between 75% and 0.1% (e.g. 75% to 4%) of the        maximum theoretical binding, and more specifically between 70%        and 0.1% (e.g. 70% to 4%) of maximum theoretical binding (as        just defined above) of the two amino acid sequences or binding        agents in combination. The Biacore assay described above is a        primary assay used to determine if amino acid sequences or other        binding agents cross-block each other according to the        invention. On rare occasions particular amino acid sequences or        other binding agents may not bind to target coupled via amine        chemistry to a CM5 Biacore chip (this usually occurs when the        relevant binding site on target is masked or destroyed by the        coupling to the chip). In such cases cross-blocking can be        determined using a tagged version of the target, for example a        N-terminal His-tagged version. In this particular format, an        anti-His amino acid sequence would be coupled to the Biacore        chip and then the His-tagged target would be passed over the        surface of the chip and captured by the anti-His amino acid        sequence. The cross blocking analysis would be carried out        essentially as described above, except that after each chip        regeneration cycle, new His-tagged target would be loaded back        onto the anti-His amino acid sequence coated surface. In        addition to the example given using N-terminal His-tagged        target, C-terminal His-tagged target could alternatively be        used.    -   Furthermore, various other tags and tag binding protein        combinations that are known in the art could be used for such a        cross-blocking analysis (e.g. HA tag with anti-HA antibodies;        FLAG tag with anti-FLAG antibodies; biotin tag with        streptavidin).    -   The following generally describes an ELISA assay for determining        whether an amino acid sequence or other binding agent directed        against a target cross-blocks or is capable of cross-blocking as        defined herein. It will be appreciated that the assay can be        used with any of the amino acid sequences (or other binding        agents such as polypeptides of the invention) described herein.        The general principal of the assay is to have an amino acid        sequence or binding agent that is directed against the target        coated onto the wells of an ELISA plate. An excess amount of a        second, potentially cross-blocking, anti-target amino acid        sequence is added in solution (i.e. not bound to the ELISA        plate). A limited amount of the target is then added to the        wells. The coated amino acid sequence and the amino acid        sequence in solution compete for binding of the limited number        of target molecules. The plate is washed to remove excess target        that has not been bound by the coated amino acid sequence and to        also remove the second, solution phase amino acid sequence as        well as any complexes formed between the second, solution phase        amino acid sequence and target. The amount of bound target is        then measured using a reagent that is appropriate to detect the        target. An amino acid sequence in solution that is able to        cross-block the coated amino acid sequence will be able to cause        a decrease in the number of target molecules that the coated        amino acid sequence can bind relative to the number of target        molecules that the coated amino acid sequence can bind in the        absence of the second, solution phase, amino acid sequence. In        the instance where the first amino acid sequence, e.g. an Ab-X,        is chosen to be the immobilized amino acid sequence, it is        coated onto the wells of the ELISA plate, after which the plates        are blocked with a suitable blocking solution to minimize        non-specific binding of reagents that are subsequently added.    -   An excess amount of the second amino acid sequence, i.e. Ab-Y,        is then added to the ELISA plate such that the moles of Ab-Y        target binding sites per well are at least 10 fold higher than        the moles of Ab-X target binding sites that were used, per well,        during the coating of the ELISA plate. Target is then added such        that the moles of target added per well are at least 25-fold        lower than the moles of Ab-X target binding sites that were used        for coating each well. Following a suitable incubation period        the ELISA plate is washed and a reagent for detecting the target        is added to measure the amount of target specifically bound by        the coated anti-target amino acid sequence (in this case Ab-X).        The background signal for the assay is defined as the signal        obtained in wells with the coated amino acid sequence (in this        case Ab-X), second solution phase amino acid sequence (in this        case Ab-Y), target buffer only (i.e. without target) and target        detection reagents. The positive control signal for the assay is        defined as the signal obtained in wells with the coated amino        acid sequence (in this case Ab-X), second solution phase amino        acid sequence buffer only (i.e. without second solution phase        amino acid sequence), target and target detection reagents. The        ELISA assay may be run in such a manner so as to have the        positive control signal be at least 6 times the background        signal. To avoid any artefacts (e.g. significantly different        affinities between Ab-X and Ab-Y for the target) resulting from        the choice of which amino acid sequence to use as the coating        amino acid sequence and which to use as the second (competitor)        amino acid sequence, the cross-blocking assay may be run in two        formats: 1) format 1 is where Ab-X is the amino acid sequence        that is coated onto the ELISA plate and Ab-Y is the competitor        amino acid sequence that is in solution and 2) format 2 is where        Ab-Y is the amino acid sequence that is coated onto the ELISA        plate and Ab-X is the competitor amino acid sequence that is in        solution. Ab-X and Ab-Y are defined as cross-blocking if, either        in format 1 or in format 2, the solution phase anti-target amino        acid sequence is able to cause a reduction of between 60% and        100%, specifically between 70% and 100%, and more specifically        between 80% and 100%, of the target detection signal (i.e. the        amount of target bound by the coated amino acid sequence) as        compared to the target detection signal obtained in the absence        of the solution phase anti-target amino acid sequence (i.e. the        positive control wells).-   v) An amino acid sequence is said to be “cross-reactive” for two    different antigens or antigenic determinants (such as serum albumin    from two different species of mammal, such as human serum albumin    and cyno serum albumin) if it is specific for (as defined herein)    both these different antigens or antigenic determinants.-   w) By binding that is “essentially independent of the pH” is    generally meant herein that the association constant (K_(A)) of the    amino acid sequence with respect to the serum protein (such as serum    albumin) at the pH value(s) that occur in a cell of an animal or    human body (as further described herein) is at least 5%, such as at    least 10%, preferably at least 25%, more preferably at least 50%,    even more preferably at least 60%, such as even more preferably at    least 70%, such as at least 80% or 90% or more (or even more than    100%, such as more than 110%, more than 120% or even 130% or more,    or even more than 150%, or even more than 200%) of the association    constant (K_(A)) of the amino acid sequence with respect to the same    serum protein at the pH value(s) that occur outside said cell.    Alternatively, by binding that is “essentially independent of the    pH” is generally meant herein that the k_(off) rate (measured by    Biacore) of the amino acid sequence with respect to the serum    protein (such as serum albumin) at the pH value(s) that occur in a    cell of an animal or human body (as e.g. further described herein,    e.g. pH around 5.5, e.g. 5.3 to 5.7) is at least 5%, such as at    least 10%, preferably at least 25%, more preferably at least 50%,    even more preferably at least 60%, such as even more preferably at    least 70%, such as at least 80% or 90% or more (or even more than    100%, such as more than 110%, more than 120% or even 130% or more,    or even more than 150%, or even more than 200%) of the k_(off) rate    of the amino acid sequence with respect to the same serum protein at    the pH value(s) that occur outside said cell, e.g. pH 7.2 to 7.4. By    “the pH value(s) that occur in a cell of an animal or human body” is    meant the pH value(s) that may occur inside a cell, and in    particular inside a cell that is involved in the recycling of the    serum protein. In particular, by “the pH value(s) that occur in a    cell of an animal or human body” is meant the pH value(s) that may    occur inside a (sub)cellular compartment or vesicle that is involved    in recycling of the serum protein (e.g. as a result of pinocytosis,    endocytosis, transcytosis, exocytosis and phagocytosis or a similar    mechanism of uptake or internalization into said cell), such as an    endosome, lysosome or pinosome.-   x) As further described herein, the total number of amino acid    residues in a Nanobody can be in the region of 110-120, is    preferably 112-115, and is most preferably 113. It should however be    noted that parts, fragments, analogs or derivatives (as further    described herein) of a Nanobody are not particularly limited as to    their length and/or size, as long as such parts, fragments, analogs    or derivatives meet the further requirements outlined herein and are    also preferably suitable for the purposes described herein;-   y) As further described in paragraph q) on pages 58 and 59 of WO    08/020079 (incorporated herein by reference), the amino acid    residues of a Nanobody are numbered according to the general    numbering for V_(H) domains given by Kabat et al. (“Sequence of    proteins of immunological interest”, US Public Health Services, NIH    Bethesda, Md., Publication No. 91), as applied to V_(HH) domains    from Camelids in the article of Riechmann and Muyldermans, J.    Immunol. Methods 2000 Jun. 23; 240 (1-2): 185-195 (see for example    FIG. 2 of this publication), and accordingly FR1 of a Nanobody    comprises the amino acid residues at positions 1-30, CDR1 of a    Nanobody comprises the amino acid residues at positions 31-35, FR2    of a Nanobody comprises the amino acids at positions 36-49, CDR2 of    a Nanobody comprises the amino acid residues at positions 50-65, FR3    of a Nanobody comprises the amino acid residues at positions 66-94,    CDR3 of a Nanobody comprises the amino acid residues at positions    95-102, and FR4 of a Nanobody comprises the amino acid residues at    positions 103-113.-   z) The Figures, Sequence Listing and the Experimental Part/Examples    are only given to further illustrate the invention and should not be    interpreted or construed as limiting the scope of the invention    and/or of the appended claims in any way, unless explicitly    indicated otherwise herein.

For a general description of heavy chain antibodies and the variabledomains thereof, reference is inter alia made to the prior art citedherein, as well as to the prior art mentioned on page 59 of WO 08/020079and to the list of references mentioned on pages 41-43 of theInternational application WO 06/040153, which prior art and referencesare incorporated herein by reference.

In accordance with the terminology used in the art (see the abovereferences), the variable domains present in naturally occurring heavychain antibodies will also be referred to as “V_(HH) domains”, in orderto distinguish them from the heavy chain variable domains that arepresent in conventional 4-chain antibodies (which will be referred tohereinbelow as “V_(H) domains”) and from the light chain variabledomains that are present in conventional 4-chain antibodies (which willbe referred to hereinbelow as “V_(L) domains”).

As mentioned in the prior art referred to above, V_(HH) domains have anumber of unique structural characteristics and functional propertieswhich make isolated V_(HH) domains (as well as Nanobodies based thereon,which share these structural characteristics and functional propertieswith the naturally occurring V_(HH) domains) and proteins containing thesame highly advantageous for use as functional antigen-binding domainsor proteins. In particular, and without being limited thereto, V_(HH)domains (which have been “designed” by nature to functionally bind to anantigen without the presence of, and without any interaction with, alight chain variable domain) and Nanobodies can function as a single,relatively small, functional antigen-binding structural unit, domain orprotein. This distinguishes the V_(HH) domains from the V_(H) and V_(L)domains of conventional 4-chain antibodies, which by themselves aregenerally not suited for practical application as single antigen-bindingproteins or domains, but need to be combined in some form or another toprovide a functional antigen-binding unit (as in for exampleconventional antibody fragments such as Fab fragments; in ScFv'sfragments, which consist of a V_(H) domain covalently linked to a V_(L)domain).

Because of these unique properties, the use of V_(HH) domains andNanobodies as single antigen-binding proteins or as antigen-bindingdomains (i.e. as part of a larger protein or polypeptide) offers anumber of significant advantages over the use of conventional V_(H) andV_(L) domains, scFv's or conventional antibody fragments (such as Fab-or F(abl-fragments), including the advantages that are listed on pages60 and 61 of WO 08/020079.

In a specific and preferred aspect, the invention provides Nanobodiesagainst OX40L, and in particular Nanobodies against OX40L from awarm-blooded animal, and more in particular Nanobodies against OX40Lfrom a mammal, and especially Nanobodies against human OX40L; as well asproteins and/or polypeptides comprising at least one such Nanobody.

In particular, the invention provides Nanobodies against OX40L, andproteins and/or polypeptides comprising the same, that have improvedtherapeutic and/or pharmacological properties and/or other advantageousproperties (such as, for example, improved ease of preparation and/orreduced costs of goods), compared to conventional antibodies againstOX40L or fragments thereof, compared to constructs that could be basedon such conventional antibodies or antibody fragments (such as Fab′fragments, F(ab′)₂ fragments, ScFv constructs, “diabodies” and othermultispecific constructs (see for example the review by Holliger andHudson, Nat Biotechnol. 2005 September; 23(9):1126-36)), and alsocompared to the so-called “dAb's” or similar (single) domain antibodiesthat may be derived from variable domains of conventional antibodies.These improved and advantageous properties will become clear from thefurther description herein, and for example include, without limitation,one or more of:

-   -   increased affinity and/or avidity for OX40L, either in a        monovalent format, in a multivalent format (for example in a        bivalent format) and/or in a multispecific format (for example        one of the multispecific formats described hereinbelow);    -   better suitability for formatting in a multivalent format (for        example in a bivalent format);    -   better suitability for formatting in a multispecific format (for        example one of the multispecific formats described hereinbelow);    -   improved suitability or susceptibility for “humanizing”        substitutions (as defined herein);    -   less immunogenicity, either in a monovalent format, in a        multivalent format (for example in a bivalent format) and/or in        a multispecific format (for example one of the multispecific        formats described hereinbelow);    -   increased stability, either in a monovalent format, in a        multivalent format (for example in a bivalent format) and/or in        a multispecific format (for example one of the multispecific        formats described hereinbelow);    -   increased specificity towards OX40L, either in a monovalent        format, in a multivalent format (for example in a bivalent        format) and/or in a multispecific format (for example one of the        multispecific formats described hereinbelow);    -   decreased or where desired increased cross-reactivity with OX40L        from different species;        and/or    -   one or more other improved properties desirable for        pharmaceutical use (including prophylactic use and/or        therapeutic use) and/or for diagnostic use (including but not        limited to use for imaging purposes), either in a monovalent        format, in a multivalent format (for example in a bivalent        format) and/or in a multispecific format (for example one of the        multispecific formats described hereinbelow).

As generally described herein for the amino acid sequences of theinvention, the Nanobodies of the invention are preferably in essentiallyisolated form (as defined herein), or form part of a protein orpolypeptide of the invention (as defined herein), which may comprise oressentially consist of one or more Nanobodies of the invention and whichmay optionally further comprise one or more further amino acid sequences(all optionally linked via one or more suitable linkers). For example,and without limitation, the one or more amino acid sequences of theinvention may be used as a binding unit in such a protein orpolypeptide, which may optionally contain one or more further amino acidsequences that can serve as a binding unit (i.e. against one or moreother targets than OX40L), so as to provide a monovalent, multivalent ormultispecific polypeptide of the invention, respectively, all asdescribed herein. In particular, such a protein or polypeptide maycomprise or essentially consist of one or more Nanobodies of theinvention and optionally one or more (other) Nanobodies (i.e. directedagainst other targets than OX40L), all optionally linked via one or moresuitable linkers, so as to provide a monovalent, multivalent ormultispecific Nanobody construct, respectively, as further describedherein. Such proteins or polypeptides may also be in essentiallyisolated form (as defined herein).

In a Nanobody of the invention, the binding site for binding againstOX40L is preferably formed by the CDR sequences. Optionally, a Nanobodyof the invention may also, and in addition to the at least one bindingsite for binding against OX40L, contain one or more further bindingsites for binding against other antigens, proteins or targets. Formethods and positions for introducing such second binding sites,reference is for example made to Keck and Huston, Biophysical Journal,71, October 1996, 2002-2011; EP 0 640 130; and WO 06/07260.

As generally described herein for the amino acid sequences of theinvention, when a Nanobody of the invention (or a polypeptide of theinvention comprising the same) is intended for administration to asubject (for example for therapeutic and/or diagnostic purposes asdescribed herein), it is preferably directed against human OX40L;whereas for veterinary purposes, it is preferably directed against OX40Lfrom the species to be treated. Also, as with the amino acid sequencesof the invention, a Nanobody of the invention may or may not becross-reactive (i.e. directed against OX40L from two or more species ofmammal, such as against human OX40L and OX40L from at least one of thespecies of mammal mentioned herein).

Also, again as generally described herein for the amino acid sequencesof the invention, the Nanobodies of the invention may generally bedirected against any antigenic determinant, epitope, part, domain,subunit or confirmation (where applicable) of OX40L.

As already described herein, the amino acid sequence and structure of aNanobody can be considered—without however being limited thereto—to becomprised of four framework regions or “FR's” (or sometimes alsoreferred to as “FW's”), which are referred to in the art and herein as“Framework region 1” or “FR1”; as “Framework region 2” or “FR2”; as“Framework region 3” or “FR3”; and as “Framework region 4” or “FR4”,respectively; which framework regions are interrupted by threecomplementary determining regions or “CDR's”, which are referred to inthe art as “Complementarity Determining Region 1” or “CDR1”; as“Complementarity Determining Region 2” or “CDR2”; and as“Complementarity Determining Region 3” or “CDR3”, respectively. Somepreferred framework sequences and CDR's (and combinations thereof) thatare present in the Nanobodies of the invention are as described herein.Other suitable CDR sequences can be obtained by the methods describedherein.

According to a non-limiting but preferred aspect of the invention, (theCDR sequences present in) the Nanobodies of the invention are such that:

-   -   the Nanobodies can bind to OX40L with a dissociation constant        (K_(D)) of 10⁻⁵ to 10⁻¹² moles/liter or less, and preferably        10⁻⁷ to 10⁻¹² moles/liter or less and more preferably 10⁻⁸ to        10⁻¹² moles/liter (i.e. with an association constant (K_(A)) of        10⁵ to 10¹² liter/moles or more, and preferably 10⁷ to 10¹²        liter/moles or more and more preferably 10⁸ to 10¹²        liter/moles);        and/or such that:    -   the Nanobodies can bind to OX40L with a k_(on)-rate of between        10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹, preferably between 10³ M⁻¹s⁻¹        and 10⁷ M⁻¹s⁻¹, more preferably between 10⁴ M⁻¹s⁻¹ and 10⁷        M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹;        and/or such that they:    -   the Nanobodies can bind to OX40L with a k_(off) rate between 1        s⁻¹ (t_(1/2)=0.69 s) and 10⁻⁶ s⁻¹ (providing a near irreversible        complex with a t_(1/2) of multiple days), preferably between        10⁻² s⁻¹ and 10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶        s⁻¹, such as between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.

Preferably, (the CDR sequences present in) the Nanobodies of theinvention are such that: a monovalent Nanobody of the invention (or apolypeptide that contains only one Nanobody of the invention) ispreferably such that it will bind to OX40L with an affinity less than500 nM, preferably less than 200 nM, more preferably less than 10 nM,such as less than 500 pM.

The affinity of the Nanobody of the invention against OX40L can bedetermined in a manner known per se, for example using the generaltechniques for measuring K_(D). K_(A), k_(off) or k_(on) mentionedherein, as well as some of the specific assays described herein.

Some preferred IC50 values for binding of the Nanobodies of theinvention (and of polypeptides comprising the same) to OX40L will becomeclear from the further description and examples herein.

In a preferred but non-limiting aspect, the invention relates to aNanobody (as defined herein) against OX40L, which consists of 4framework regions (FR1 to FR4 respectively) and 3 complementaritydetermining regions (CDR1 to CDR3 respectively), in which:

-   -   CDR1 is chosen from the group consisting of:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;

-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;

-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;    and/or    -   CDR2 is chosen from the group consisting of:

-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;

-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;

-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;    and/or    -   CDR3 is chosen from the group consisting of:

-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;

-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;

-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;    or any suitable fragment of such an amino acid sequence.

In particular, according to this preferred but non-limiting aspect, theinvention relates to a Nanobody (as defined herein) against OX40L, whichconsists of 4 framework regions (FR1 to FR4 respectively) and 3complementarity determining regions (CDR1 to CDR3 respectively), inwhich:

-   -   CDR1 is chosen from the group consisting of:

-   a) the amino acid sequences of SEQ ID NO's: 133 to 139;

-   b) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;

-   c) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 133 to    139;    and    -   CDR2 is chosen from the group consisting of:

-   d) the amino acid sequences of SEQ ID NO's: 147 to 153;

-   e) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;

-   f) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 147 to    153;    and    -   CDR3 is chosen from the group consisting of:

-   g) the amino acid sequences of SEQ ID NO's: 161 to 167;

-   h) amino acid sequences that have at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;

-   i) amino acid sequences that have 3, 2, or 1 amino acid difference    with at least one of the amino acid sequences of SEQ ID NO's: 161 to    167;    or any suitable fragment of such an amino acid sequences.

As generally mentioned herein for the amino acid sequences of theinvention, when a Nanobody of the invention contains one or more CDR1sequences according to b) and/or c):

-   i) any amino acid substitution in such a CDR according to b)    and/or c) is preferably, and compared to the corresponding CDR    according to a), a conservative amino acid substitution (as defined    herein);    and/or-   ii) the CDR according to b) and/or c) preferably only contains amino    acid substitutions, and no amino acid deletions or insertions,    compared to the corresponding CDR according to a);    and/or-   iii) the CDR according to b) and/or c) may be a CDR that is derived    from a CDR according to a) by means of affinity maturation using one    or more techniques of affinity maturation known per se.

Similarly, when a Nanobody of the invention contains one or more CDR2sequences according to e) and/or f):

-   i) any amino acid substitution in such a CDR according to e)    and/or f) is preferably, and compared to the corresponding CDR    according to d), a conservative amino acid substitution (as defined    herein);    and/or-   ii) the CDR according to e) and/or f) preferably only contains amino    acid substitutions, and no amino acid deletions or insertions,    compared to the corresponding CDR according to d);    and/or-   iii) the CDR according to e) and/or f) may be a CDR that is derived    from a CDR according to d) by means of affinity maturation using one    or more techniques of affinity maturation known per se.

Also, similarly, when a Nanobody of the invention contains one or moreCDR3 sequences according to h) and/or i):

-   i) any amino acid substitution in such a CDR according to h)    and/or i) is preferably, and compared to the corresponding CDR    according to g), a conservative amino acid substitution (as defined    herein);    and/or-   ii) the CDR according to h) and/or i) preferably only contains amino    acid substitutions, and no amino acid deletions or insertions,    compared to the corresponding CDR according to g); and/or-   iii) the CDR according to h) and/or i) may be a CDR that is derived    from a CDR according to g) by means of affinity maturation using one    or more techniques of affinity maturation known per se.

It should be understood that the last three paragraphs generally applyto any Nanobody of the invention that comprises one or more CDR1sequences, CDR2 sequences and/or CDR3 sequences according to b), c), e),f), h) or i), respectively.

Of the Nanobodies of the invention, Nanobodies comprising one or more ofthe CDR's explicitly listed above are particularly preferred; Nanobodiescomprising two or more of the CDR's explicitly listed above are moreparticularly preferred; and Nanobodies comprising three of the CDR'sexplicitly listed above are most particularly preferred.

Some particularly preferred, but non-limiting combinations of CDRsequences, as well as preferred combinations of CDR sequences andframework sequences, are mentioned in Table B-1 below, which lists theCDR sequences and framework sequences that are present in a number ofpreferred (but non-limiting) Nanobodies of the invention. As will beclear to the skilled person, a combination of CDR1, CDR2 and CDR3sequences that occur in the same clone (i.e. CDR1, CDR2 and CDR3sequences that are mentioned on the same line in Table B-1) will usuallybe preferred (although the invention in its broadest sense is notlimited thereto, and also comprises other suitable combinations of theCDR sequences mentioned in Table B-1). Also, a combination of CDRsequences and framework sequences that occur in the same clone (i.e. CDRsequences and framework sequences that are mentioned on the same line inTable B-1) will usually be preferred (although the invention in itsbroadest sense is not limited thereto, and also comprises other suitablecombinations of the CDR sequences and framework sequences mentioned inTable B-1, as well as combinations of such CDR sequences and othersuitable framework sequences, e.g. as further described herein).

Also, in the Nanobodies of the invention that comprise the combinationsof CDR's mentioned in Table B-1, each CDR can be replaced by a CDRchosen from the group consisting of amino acid sequences that have atleast 80%, preferably at least 90%, more preferably at least 95%, evenmore preferably at least 99% sequence identity (as defined herein) withthe mentioned CDR's; in which:

-   i) any amino acid substitution in such a CDR is preferably, and    compared to the corresponding CDR sequence mentioned in Table B-1, a    conservative amino acid substitution (as defined herein);    and/or-   ii) any such CDR sequence preferably only contains amino acid    substitutions, and no amino acid deletions or insertions, compared    to the corresponding CDR sequence mentioned in Table B-1;    and/or-   iii) any such CDR sequence is a CDR that is derived by means of a    technique for affinity maturation known per se, and in particular    starting from the corresponding CDR sequence mentioned in Table B-1.

However, as will be clear to the skilled person, the (combinations of)CDR sequences, as well as (the combinations of) CDR sequences andframework sequences mentioned in Table B-1 will generally be preferred.

TABLE B-1 Preferred combinations of CDR sequences, preferred combinations of framework sequences, andpreferred combinations of framework and CDR sequences.  (“ID”refers to the SEQ ID NO as used herein) ID FR1 ID CDR1 ID FR2 ID CDR2 IDFR3 ID CDR3 ID FR4 126 EVQLVESGGG 133 LDRMG 140 WYRHRTG 147 TITGGSSI 154RFTISIDNAKN 161 NKYVTSR 168 WGQGTQ LVQAGGSLRL EPRELVA NYGDFVKGTVYLQMNNLKP DT VTVSS SCAASRSIGR EDTAVYYCNF 127 EVQLVESGGG 134 TYIMG 141WFRQAPG 148 TISRSGITT 155 RFTISRDNAKN 162 GPYVEQT 169 WGQGTQ LVQAGGSLRLKEREFVA RSADSVKG TVYLQMNSLKP LGLYQTL VTVSS SCVASGRSFS EDTAVYYCAA GPWDY128 EVQLVESGGG 135 SIYAKG 142 WFRQAPG 149 AISRSGRST 156 RFTISRDNAKN 163VGGATTV 170 WGLGTQ LVQAGGSLRL KEREFVA SYADSVKG TVYLQMNSLKP TASEWDY VTVSSSCAASGRTFS EDTAVYYCAA 129 EVQLVESGGG 136 SFAMG 143 WFRQAPG 150 AISRSGYGT157 RFIISRDNAKN 164 EHTLGRP 171 WGQGTQ LVQAGDSLRL KEREFVA SEADSVRDTVTLHLSRLKP SRSQINY VTVSS SCAASGLTFS EDTAVYYCAA LY 130 EVQLVESGGG 137LNTMG 144 WYRHAPG 151 RISSNSKT 158 RFTISRDNAKN 165 NVWRTSS 172 WGQGTQLVQAGGSLRL KPRELVA DYADSVKG TVLLQMNSLKP DY VTVSS SCAASRNILS EDTGVYYCNL131 EVQLVESGGG 138 DYAIA 145 WFRQAPG 152 RIKISNGRT 159 RFTISSDNAKN 166DRSSLLF 173 WGQGTQ LVQAGGSLRL KEREGVS TYAGSVKG TVYLQMNSLNA GSNWDRK VTVSSSCAASGFTLD EDTAVYYCAA ARYDY 132 EVQLVESGGG 139 SNYAMG 146 WFRQAPG 153AISRSGSIT 160 RFSISRDYAKS 167 DGGAVRD 174 WGRGTQ LVQAGASLRL QERAFVAYYTDSVKG TVYLQMDNLKP LTTNLPD VTVSS SCAASGRRFI EDTAVYYCAA Y

Thus, in the Nanobodies of the invention, at least one of the CDR1, CDR2and CDR3 sequences present is suitably chosen from the group consistingof the CDR1, CDR2 and CDR3 sequences, respectively, listed in Table B-1;or from the group of CDR1, CDR2 and CDR3 sequences, respectively, thathave at least 80%, preferably at least 90%, more preferably at least95%, even more preferably at least 99% “sequence identity” (as definedherein) with at least one of the CDR1, CDR2 and CDR3 sequences,respectively, listed in Table B-1; and/or from the group consisting ofthe CDR1, CDR2 and CDR3 sequences, respectively, that have 3, 2 or only1 “amino acid difference(s)” (as defined herein) with at least one ofthe CDR1, CDR2 and CDR3 sequences, respectively, listed in Table B-1.

In this context, by “suitably chosen” is meant that, as applicable, aCDR1 sequence is chosen from suitable CDR1 sequences (i.e. as definedherein), a CDR2 sequence is chosen from suitable CDR2 sequences (i.e. asdefined herein), and a CDR3 sequence is chosen from suitable CDR3sequence (i.e. as defined herein), respectively. More in particular, theCDR sequences are preferably chosen such that the Nanobodies of theinvention bind to OX40L with an affinity (suitably measured and/orexpressed as a K_(D)-value (actual or apparent), a K_(A)-value (actualor apparent), a k_(on)-rate and/or a k_(off)-rate, or alternatively asan IC₅₀ value, as further described herein) that is as defined herein.

In particular, in the Nanobodies of the invention, at least the CDR3sequence present is suitably chosen from the group consisting of theCDR3 sequences listed in Table B-1 or from the group of CDR3 sequencesthat have at least 80%, preferably at least 90%, more preferably atleast 95%, even more preferably at least 99% sequence identity with atleast one of the CDR3 sequences listed in Table B-1; and/or from thegroup consisting of the CDR3 sequences that have 3, 2 or only 1 aminoacid difference(s) with at least one of the CDR3 sequences listed inTable B-1.

Preferably, in the Nanobodies of the invention, at least two of theCDR1, CDR2 and CDR3 sequences present are suitably chosen from the groupconsisting of the CDR1, CDR2 and CDR3 sequences, respectively, listed inTable B-1 or from the group consisting of CDR1, CDR2 and CDR3 sequences,respectively, that have at least 80%, preferably at least 90%, morepreferably at least 95%, even more preferably at least 99% sequenceidentity with at least one of the CDR1, CDR2 and CDR3 sequences,respectively, listed in Table B-1; and/or from the group consisting ofthe CDR1, CDR2 and CDR3 sequences, respectively, that have 3, 2 or only1 “amino acid difference(s)” with at least one of the CDR1, CDR2 andCDR3 sequences, respectively, listed in Table B-1.

In particular, in the Nanobodies of the invention, at least the CDR3sequence present is suitably chosen from the group consisting of theCDR3 sequences listed in Table B-1 or from the group of CDR3 sequencesthat have at least 80%, preferably at least 90%, more preferably atleast 95%, even more preferably at least 99% sequence identity with atleast one of the CDR3 sequences listed in Table B-1, respectively; andat least one of the CDR1 and CDR2 sequences present is suitably chosenfrom the group consisting of the CDR1 and CDR2 sequences, respectively,listed in Table B-1 or from the group of CDR1 and CDR2 sequences,respectively, that have at least 80%, preferably at least 90%, morepreferably at least 95%, even more preferably at least 99% sequenceidentity with at least one of the CDR1 and CDR2 sequences, respectively,listed in Table B-1; and/or from the group consisting of the CDR1 andCDR2 sequences, respectively, that have 3, 2 or only 1 amino aciddifference(s) with at least one of the CDR1 and CDR2 sequences,respectively, listed in Table B-1.

Most preferably, in the Nanobodies of the invention, all three CDR1,CDR2 and CDR3 sequences present are suitably chosen from the groupconsisting of the CDR1, CDR2 and CDR3 sequences, respectively, listed inTable B-1 or from the group of CDR1, CDR2 and CDR3 sequences,respectively, that have at least 80%, preferably at least 90%, morepreferably at least 95%, even more preferably at least 99% sequenceidentity with at least one of the CDR1, CDR2 and CDR3 sequences,respectively, listed in Table B-1; and/or from the group consisting ofthe CDR1, CDR2 and CDR3 sequences, respectively, that have 3, 2 or only1 amino acid difference(s) with at least one of the CDR1, CDR2 and CDR3sequences, respectively, listed in Table B-1.

Even more preferably, in the Nanobodies of the invention, at least oneof the CDR1, CDR2 and CDR3 sequences present is suitably chosen from thegroup consisting of the CDR1, CDR2 and CDR3 sequences, respectively,listed in Table B-1. Preferably, in this aspect, at least one orpreferably both of the other two CDR sequences present are suitablychosen from CDR sequences that have at least 80%, preferably at least90%, more preferably at least 95%, even more preferably at least 99%sequence identity with at least one of the corresponding CDR sequences,respectively, listed in Table B-1; and/or from the group consisting ofthe CDR sequences that have 3, 2 or only 1 amino acid difference(s) withat least one of the corresponding sequences, respectively, listed inTable B-1.

In particular, in the Nanobodies of the invention, at least the CDR3sequence present is suitably chosen from the group consisting of theCDR3 listed in Table B-1. Preferably, in this aspect, at least one andpreferably both of the CDR1 and CDR2 sequences present are suitablychosen from the groups of CDR1 and CDR2 sequences, respectively, thathave at least 80%, preferably at least 90%, more preferably at least95%, even more preferably at least 99% sequence identity with the CDR1and CDR2 sequences, respectively, listed in Table B-1; and/or from thegroup consisting of the CDR1 and CDR2 sequences, respectively, that have3, 2 or only 1 amino acid difference(s) with at least one of the CDR1and CDR2 sequences, respectively, listed in Table B-1.

Even more preferably, in the Nanobodies of the invention, at least twoof the CDR1, CDR2 and CDR3 sequences present are suitably chosen fromthe group consisting of the CDR1, CDR2 and CDR3 sequences, respectively,listed in Table B-1. Preferably, in this aspect, the remaining CDRsequence present is suitably chosen from the group of CDR sequences thathave at least 80%, preferably at least 90%, more preferably at least95%, even more preferably at least 99% sequence identity with at leastone of the corresponding CDR sequences listed in Table B-1; and/or fromthe group consisting of CDR sequences that have 3, 2 or only 1 aminoacid difference(s) with at least one of the corresponding sequenceslisted in Table B-1.

In particular, in the Nanobodies of the invention, at least the CDR3sequence is suitably chosen from the group consisting of the CDR3sequences listed in Table B-1, and either the CDR1 sequence or the CDR2sequence is suitably chosen from the group consisting of the CDR1 andCDR2 sequences, respectively, listed in Table B-1. Preferably, in thisaspect, the remaining CDR sequence present is suitably chosen from thegroup of CDR sequences that have at least 80%, preferably at least 90%,more preferably at least 95%, even more preferably at least 99% sequenceidentity with at least one of the corresponding CDR sequences listed inTable B-1; and/or from the group consisting of CDR sequences that have3, 2 or only 1 amino acid difference(s) with the corresponding CDRsequences listed in Table B-1.

Even more preferably, in the Nanobodies of the invention, all threeCDR1, CDR2 and CDR3 sequences present are suitably chosen from the groupconsisting of the CDR1, CDR2 and CDR3 sequences, respectively, listed inTable B-1.

Also, generally, the combinations of CDR's listed in Table B-1 (i.e.those mentioned on the same line in Table B-1) are preferred. Thus, itis generally preferred that, when a CDR in a Nanobody of the inventionis a CDR sequence mentioned in Table B-1 or is suitably chosen from thegroup of CDR sequences that have at least 80%, preferably at least 90%,more preferably at least 95%, even more preferably at least 99% sequenceidentity with a CDR sequence listed in Table B-1; and/or from the groupconsisting of CDR sequences that have 3, 2 or only 1 amino aciddifference(s) with a CDR sequence listed in Table B-1, that at least oneand preferably both of the other CDR's are suitably chosen from the CDRsequences that belong to the same combination in Table B-1 (i.e.mentioned on the same line in Table B-1) or are suitably chosen from thegroup of CDR sequences that have at least 80%, preferably at least 90%,more preferably at least 95%, even more preferably at least 99% sequenceidentity with the CDR sequence(s) belonging to the same combinationand/or from the group consisting of CDR sequences that have 3, 2 or only1 amino acid difference(s) with the CDR sequence(s) belonging to thesame combination. The other preferences indicated in the aboveparagraphs also apply to the combinations of CDR's mentioned in TableB-1.

Thus, by means of non-limiting examples, a Nanobody of the invention canfor example comprise a CDR1 sequence that has more than 80% sequenceidentity with one of the CDR1 sequences mentioned in Table B-1, a CDR2sequence that has 3, 2 or 1 amino acid difference with one of the CDR2sequences mentioned in Table B-1 (but belonging to a differentcombination), and a CDR3 sequence.

Some preferred Nanobodies of the invention may for example comprise: (1)a CDR1 sequence that has more than 80% sequence identity with one of theCDR1 sequences mentioned in Table B-1; a CDR2 sequence that has 3, 2 or1 amino acid difference with one of the CDR2 sequences mentioned inTable B-1 (but belonging to a different combination); and a CDR3sequence that has more than 80% sequence identity with one of the CDR3sequences mentioned in Table B-1 (but belonging to a differentcombination); or (2) a CDR1 sequence that has more than 80% sequenceidentity with one of the CDR1 sequences mentioned in Table B-1; a CDR2sequence, and one of the CDR3 sequences listed in Table B-1; or (3) aCDR1 sequence; a CDR2 sequence that has more than 80% sequence identitywith one of the CDR2 sequence listed in Table B-1; and a CDR3 sequencethat has 3, 2 or 1 amino acid differences with the CDR3 sequencementioned in Table B-1 that belongs to the same combination as the CDR2sequence.

Some particularly preferred Nanobodies of the invention may for examplecomprise: (1) a CDR1 sequence that has more than 80% sequence identitywith one of the CDR1 sequences mentioned in Table B-1; a CDR2 sequencethat has 3, 2 or 1 amino acid difference with the CDR2 sequencementioned in Table B-1 that belongs to the same combination; and a CDR3sequence that has more than 80% sequence identity with the CDR3 sequencementioned in Table B-1 that belongs to the same combination; (2) a CDR1sequence; a CDR 2 listed in Table B-1 and a CDR3 sequence listed inTable B-1 (in which the CDR2 sequence and CDR3 sequence may belong todifferent combinations).

Some even more preferred Nanobodies of the invention may for examplecomprise: (1) a CDR1 sequence that has more than 80% sequence identitywith one of the CDR1 sequences mentioned in Table B-1; the CDR2 sequencelisted in Table B-1 that belongs to the same combination; and a CDR3sequence mentioned in Table B-1 that belongs to a different combination;or (2) a CDR1 sequence mentioned in Table B-1; a CDR2 sequence that has3, 2 or 1 amino acid differences with the CDR2 sequence mentioned inTable B-1 that belongs to the same combination; and a CDR3 sequence thathas more than 80% sequence identity with the CDR3 sequence listed inTable B-1 that belongs to the same or a different combination.

Particularly preferred Nanobodies of the invention may for examplecomprise a CDR1 sequence mentioned in Table B-1, a CDR2 sequence thathas more than 80% sequence identity with the CDR2 sequence mentioned inTable B-1 that belongs to the same combination; and the CDR3 sequencementioned in Table B-1 that belongs to the same combination.

In the most preferred Nanobodies of the invention, the CDR1, CDR2 andCDR3 sequences present are suitably chosen from one of the combinationsof CDR1, CDR2 and CDR3 sequences, respectively, listed in Table B-1.

According to another preferred, but non-limiting aspect of the invention(a) CDR1 has a length of between 1 and 12 amino acid residues, andusually between 2 and 9 amino acid residues, such as 5, 6 or 7 aminoacid residues; and/or (b) CDR2 has a length of between 13 and 24 aminoacid residues, and usually between 15 and 21 amino acid residues, suchas 16 and 17 amino acid residues; and/or (c) CDR3 has a length ofbetween 2 and 35 amino acid residues, and usually between 3 and 30 aminoacid residues, such as between 6 and 23 amino acid residues.

In another preferred, but non-limiting aspect, the invention relates toa Nanobody in which the CDR sequences (as defined herein) have more than80%, preferably more than 90%, more preferably more than 95%, such as99% or more sequence identity (as defined herein) with the CDR sequencesof at least one of the amino acid sequences of SEQ ID NO's: 179 to 185(see Table A-1).

Generally, Nanobodies with the above CDR sequences may be as furtherdescribed herein, and preferably have framework sequences that are alsoas further described herein. Thus, for example and as mentioned herein,such Nanobodies may be naturally occurring Nanobodies (from any suitablespecies), naturally occurring V_(HH) sequences (i.e. from a suitablespecies of Camelid) or synthetic or semi-synthetic amino acid sequencesor Nanobodies, including but not limited to partially humanizedNanobodies or V_(HH) sequences, fully humanized Nanobodies or V_(HH)sequences, camelized heavy chain variable domain sequences, as well asNanobodies that have been obtained by the techniques mentioned herein.

Thus, in one specific, but non-limiting aspect, the invention relates toa humanized Nanobody, which consists of 4 framework regions (FR1 to FR4respectively) and 3 complementarity determining regions (CDR1 to CDR3respectively), in which CDR1 to CDR3 are as defined herein and in whichsaid humanized Nanobody comprises at least one humanizing substitution(as defined herein), and in particular at least one humanizingsubstitution in at least one of its framework sequences (as definedherein).

In another preferred, but non-limiting aspect, the invention relates toa Nanobody in which the CDR sequences have at least 70% amino acididentity, preferably at least 80% amino acid identity, more preferablyat least 90% amino acid identity, such as 95% amino acid identity ormore or even essentially 100% amino acid identity with the CDR sequencesof at least one of the amino acid sequences of SEQ ID NO's: 179 to 185(see Table A-1). This degree of amino acid identity can for example bedetermined by determining the degree of amino acid identity (in a mannerdescribed herein) between said Nanobody and one or more of the sequencesof SEQ ID NO's: 179 to 185 (see Table A-1), in which the amino acidresidues that form the framework regions are disregarded. SuchNanobodies can be as further described herein.

In another preferred, but non-limiting aspect, the invention relates toa Nanobody with an amino acid sequence that is chosen from the groupconsisting of SEQ ID NO's: 179 to 185 (see Table A-1) or from the groupconsisting of from amino acid sequences that have more than 80%,preferably more than 90%, more preferably more than 95%, such as 99% ormore sequence identity (as defined herein) with at least one of theamino acid sequences of SEQ ID NO's: 179 to 185 (see Table A-1).

Another preferred, but non-limiting aspect of the invention relates tohumanized and/or sequence optimized variants of the Nanobodies of SEQ IDNO's: 179 to 185 (see Table A-1), that comprise, compared to thecorresponding native V_(HH) sequence, at least one humanizing and/orsequence optimizing substitution (as defined herein), and in particularat least one humanizing and/or sequence optimizing substitution in atleast one of its framework sequences (as defined herein). Somepreferred, but non-limiting examples of such humanized and/or sequenceoptimized variants are the humanized and/or sequence optimizedNanobodies of SEQ ID NO's: 199 to 226 (see Table A-2). Thus, theinvention also relates to a humanized and/or sequence optimized Nanobodywith an amino acid sequence that is chosen from the group consisting ofSEQ ID NO's: 199 to 226 (see Table A-2) or from the group consisting offrom amino acid sequences that have more than 80%, preferably more than90%, more preferably more than 95%, such as 99% or more sequenceidentity (as defined herein) with at least one of the amino acidsequences of SEQ ID NO's: 199 to 226 (see Table A-2) (in which aminoacid sequences that are chosen from the latter group of amino acidsequences may contain a greater number or a smaller number of humanizingand/or sequence optimizing substitutions compared to the correspondingsequence of SEQ ID NO's: 199 to 226 (see Table A-2), as long as theyretain at least one of the humanizing and/or sequence optimizingsubstitutions present in the corresponding sequence of SEQ ID NO's: 199to 226 (see Table A-2)).

The polypeptides of the invention comprise or essentially consist of atleast one Nanobody of the invention. Some preferred, but non-limitingexamples of polypeptides of the invention are given in SEQ ID NO's: 186to 198 (see Table A-3) and SEQ ID NO's: 227 to 234 (see Table A-4).

It will be clear to the skilled person that the Nanobodies that arementioned herein as “preferred” (or “more preferred”, “even morepreferred”, etc.) are also preferred (or more preferred, or even morepreferred, etc.) for use in the polypeptides described herein. Thus,polypeptides that comprise or essentially consist of one or more“preferred” Nanobodies of the invention will generally be preferred, andpolypeptides that comprise or essentially consist of one or more “morepreferred” Nanobodies of the invention will generally be more preferred,etc.

Generally, proteins or polypeptides that comprise or essentially consistof a single Nanobody (such as a single Nanobody of the invention) willbe referred to herein as “monovalent” proteins or polypeptides or as“monovalent constructs”. Proteins and polypeptides that comprise oressentially consist of two or more Nanobodies (such as at least twoNanobodies of the invention or at least one Nanobody of the inventionand at least one other Nanobody) will be referred to herein as“multivalent” proteins or polypeptides or as “multivalent constructs”,and these may provide certain advantages compared to the correspondingmonovalent Nanobodies of the invention. Some non-limiting examples ofsuch multivalent constructs will become clear from the furtherdescription herein.

According to one specific, but non-limiting aspect, a polypeptide of theinvention comprises or essentially consists of at least two Nanobodiesof the invention, such as two or three Nanobodies of the invention. Asfurther described herein, such multivalent constructs can providecertain advantages compared to a protein or polypeptide comprising oressentially consisting of a single Nanobody of the invention, such as amuch improved avidity for OX40L. Such multivalent constructs will beclear to the skilled person based on the disclosure herein; somepreferred, but non-limiting examples of such multivalent Nanobodyconstructs are the constructs of SEQ ID NO's: 186 to 198 and 227 to 234,more preferably constructs of SEQ ID NO's: 186, 187, 189, 190, 227, 228,229, 230, 231, 233; most preferred construct of SEQ ID NO's: 190, 227,228, 231 and 233.

According to another specific, but non-limiting aspect, a polypeptide ofthe invention comprises or essentially consists of at least one Nanobodyof the invention and at least one other binding unit (i.e. directedagainst another epitope, antigen, target, protein or polypeptide), whichis preferably also a Nanobody. Such proteins or polypeptides are alsoreferred to herein as “multispecific” proteins or polypeptides or as“multispecific constructs”, and these may provide certain advantagescompared to the corresponding monovalent Nanobodies of the invention (aswill become clear from the further discussion herein of some preferred,but-nonlimiting multispecific constructs). Such multispecific constructswill be clear to the skilled person based on the disclosure herein; somepreferred, but non-limiting examples of such multispecific Nanobodyconstructs are the constructs of SEQ ID NO's: 186 to 198 and 227 to 234,more preferably constructs of SEQ ID NO's: 186, 187, 189, 190, 227, 228,229, 230, 231, 233; most preferred construct of SEQ ID NO's: 190, 227,228, 231 and 233.

According to yet another specific, but non-limiting aspect, apolypeptide of the invention comprises or essentially consists of atleast one Nanobody of the invention, optionally one or more furtherNanobodies, and at least one other amino acid sequence (such as aprotein or polypeptide) that confers at least one desired property tothe Nanobody of the invention and/or to the resulting fusion protein.Again, such fusion proteins may provide certain advantages compared tothe corresponding monovalent Nanobodies of the invention. Somenon-limiting examples of such amino acid sequences and of such fusionconstructs will become clear from the further description herein.

It is also possible to combine two or more of the above aspects, forexample to provide a trivalent bispecific construct comprising twoNanobodies of the invention and one other Nanobody, and optionally oneor more other amino acid sequences. Further non-limiting examples ofsuch constructs, as well as some constructs that are particularlypreferred within the context of the present invention, will become clearfrom the further description herein.

In the above constructs, the one or more Nanobodies and/or other aminoacid sequences may be directly linked to each other and/or suitablylinked to each other via one or more linker sequences. Some suitable butnon-limiting examples of such linkers will become clear from the furtherdescription herein.

In one specific aspect of the invention, a Nanobody of the invention ora compound, construct or polypeptide of the invention comprising atleast one Nanobody of the invention may have an increased half-life,compared to the corresponding amino acid sequence of the invention.

Some preferred, but non-limiting examples of such Nanobodies, compoundsand polypeptides will become clear to the skilled person based on thefurther disclosure herein, and for example comprise Nanobodies sequencesor polypeptides of the invention that have been chemically modified toincrease the half-life thereof (for example, by means of pegylation);amino acid sequences of the invention that comprise at least oneadditional binding site for binding to a serum protein (such as serumalbumin, see for example EP 0 368 684 B1, page 4); or polypeptides ofthe invention that comprise at least one Nanobody of the invention thatis linked to at least one moiety (and in particular at least one aminoacid sequence) that increases the half-life of the Nanobody of theinvention. Examples of polypeptides of the invention that comprise suchhalf-life extending moieties or amino acid sequences will become clearto the skilled person based on the further disclosure herein; and forexample include, without limitation, polypeptides in which the one ormore Nanobodies of the invention are suitable linked to one or moreserum proteins or fragments thereof (such as serum albumin or suitablefragments thereof) or to one or more binding units that can bind toserum proteins (such as, for example, Nanobodies or (single) domainantibodies that can bind to serum proteins such as serum albumin, serumimmunoglobulins such as IgG, or transferrin); polypeptides in which aNanobody of the invention is linked to an Fc portion (such as a humanFc) or a suitable part or fragment thereof; or polypeptides in which theone or more Nanobodies of the invention are suitable linked to one ormore small proteins or peptides that can bind to serum proteins (suchas, without limitation, the proteins and peptides described in WO91/01743, WO 01/45746, WO 02/076489 and to the US provisionalapplication of Ablynx N.V. entitled “Peptides capable of binding toserum proteins” of Ablynx N.V. filed on Dec. 5, 2006 (see alsoPCT/EP/2007/063348).

Again, as will be clear to the skilled person, such Nanobodies,compounds, constructs or polypeptides may contain one or more additionalgroups, residues, moieties or binding units, such as one or more furtheramino acid sequences and in particular one or more additional Nanobodies(i.e. not directed against OX40L), so as to provide a tri- ofmultispecific Nanobody construct.

Generally, the Nanobodies of the invention (or compounds, constructs orpolypeptides comprising the same) with increased half-life preferablyhave a half-life that is at least 1.5 times, preferably at least 2times, such as at least 5 times, for example at least 10 times or morethan 20 times, greater than the half-life of the corresponding aminoacid sequence of the invention per se. For example, the Nanobodies,compounds, constructs or polypeptides of the invention with increasedhalf-life may have a half-life that is increased with more than 1 hours,preferably more than 2 hours, more preferably more than 6 hours, such asmore than 12 hours, or even more than 24, 48 or 72 hours, compared tothe corresponding amino acid sequence of the invention per se.

In a preferred, but non-limiting aspect of the invention, suchNanobodies, compound, constructs or polypeptides of the inventionexhibit a serum half-life in human of at least about 12 hours,preferably at least 24 hours, more preferably at least 48 hours, evenmore preferably at least 72 hours or more. For example, compounds orpolypeptides of the invention may have a half-life of at least 5 days(such as about 5 to 10 days), preferably at least 9 days (such as about9 to 14 days), more preferably at least about 10 days (such as about 10to 15 days), or at least about 11 days (such as about 11 to 16 days),more preferably at least about 12 days (such as about 12 to 18 days ormore), or more than 14 days (such as about 14 to 19 days).

In another one aspect of the invention, a polypeptide of the inventioncomprises one or more (such as two or preferably one) Nanobodies of theinvention linked (optionally via one or more suitable linker sequences)to one or more (such as two and preferably one) amino acid sequencesthat allow the resulting polypeptide of the invention to cross the bloodbrain barrier. In particular, said one or more amino acid sequences thatallow the resulting polypeptides of the invention to cross the bloodbrain barrier may be one or more (such as two and preferably one)Nanobodies, such as the Nanobodies described in WO 02/057445, of whichFC44 (SEQ ID NO: 189 of WO 06/040153) and FC5 (SEQ ID NO: 190 of WO06/040154) are preferred examples.

In particular, polypeptides comprising one or more Nanobodies of theinvention are preferably such that they:

-   -   bind to OX40L with a dissociation constant (K_(D)) of 10⁻⁵ to        10⁻¹² moles/liter or less, and preferably 10⁻⁷ to 10⁻¹²        moles/liter or less and more preferably 10⁻⁸ to 10⁻¹²        moles/liter (i.e. with an association constant (K_(A)) of 10⁵ to        10¹² liter/moles or more, and preferably 10⁷ to 10¹² liter/moles        or more and more preferably 10⁸ to 10¹² liter/moles);        and/or such that they:    -   bind to OX40L with a k_(on)-rate of between 10² M⁻¹s⁻¹ to about        10⁷ M⁻¹s⁻¹, preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more        preferably between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between        10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹;        and/or such that they:    -   bind to OX40L with a k_(off) rate between 1 s⁻¹ (t_(1/2)=0.69 s)        and 10⁻⁶s⁻¹ (providing a near irreversible complex with a        t_(1/2) of multiple days), preferably between 10⁻²s⁻¹ and 10⁻⁶        s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as        between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.

Preferably, a polypeptide that contains only one amino acid sequence ofthe invention is preferably such that it will bind to OX40L with anaffinity less than 500 nM, preferably less than 200 nM, more preferablyless than 10 nM, such as less than 500 pM. In this respect, it will beclear to the skilled person that a polypeptide that contains two or moreNanobodies of the invention may bind to OX40L with an increased avidity,compared to a polypeptide that contains only one amino acid sequence ofthe invention.

Some preferred IC₅₀ values for binding of the amino acid sequences orpolypeptides of the invention to OX40L will become clear from thefurther description and examples herein.

Other polypeptides according to this preferred aspect of the inventionmay for example be chosen from the group consisting of amino acidsequences that have more than 80%, preferably more than 90%, morepreferably more than 95%, such as 99% or more “sequence identity” (asdefined herein) with one or more of the amino acid sequences of SEQ IDNO's: 186 to 198 (see Table A-3) and SEQ ID NO's: 227 to 234 (TableA-4), in which the Nanobodies comprised within said amino acid sequencesare preferably as further defined herein.

Another aspect of this invention relates to a nucleic acid that encodesan amino acid sequence of the invention (such as a Nanobody of theinvention) or a polypeptide of the invention comprising the same. Again,as generally described herein for the nucleic acids of the invention,such a nucleic acid may be in the form of a genetic construct, asdefined herein.

In another aspect, the invention relates to host or host cell thatexpresses or that is capable of expressing an amino acid sequence (suchas a Nanobody) of the invention and/or a polypeptide of the inventioncomprising the same; and/or that contains a nucleic acid of theinvention. Some preferred but non-limiting examples of such hosts orhost cells will become clear from the further description herein.

Another aspect of the invention relates to a product or compositioncontaining or comprising at least one amino acid sequence of theinvention, at least one polypeptide of the invention and/or at least onenucleic acid of the invention, and optionally one or more furthercomponents of such compositions known per se, i.e. depending on theintended use of the composition. Such a product or composition may forexample be a pharmaceutical composition (as described herein), aveterinary composition or a product or composition for diagnostic use(as also described herein). Some preferred but non-limiting examples ofsuch products or compositions will become clear from the furtherdescription herein.

The invention further relates to methods for preparing or generating theamino acid sequences, compounds, constructs, polypeptides, nucleicacids, host cells, products and compositions described herein. Somepreferred but non-limiting examples of such methods will become clearfrom the further description herein.

The invention further relates to applications and uses of the amino acidsequences, compounds, constructs, polypeptides, nucleic acids, hostcells, products and compositions described herein, as well as to methodsfor the prevention and/or treatment for diseases and disordersassociated with OX40L. Some preferred but non-limiting applications anduses will become clear from the further description herein.

Other aspects, embodiments, advantages and applications of the inventionwill also become clear from the further description hereinbelow.

Generally, it should be noted that the term Nanobody as used herein inits broadest sense is not limited to a specific biological source or toa specific method of preparation. For example, as will be discussed inmore detail below, the Nanobodies of the invention can generally beobtained by any of the techniques (1) to (8) mentioned on pages 61 and62 of WO 08/020079, or any other suitable technique known per se. Onepreferred class of Nanobodies corresponds to the V_(HH) domains ofnaturally occurring heavy chain antibodies directed against OX40L. Asfurther described herein, such V_(HH) sequences can generally begenerated or obtained by suitably immunizing a species of Camelid withOX40L (i.e. so as to raise an immune response and/or heavy chainantibodies directed against OX40L), by obtaining a suitable biologicalsample from said Camelid (such as a blood sample, serum sample or sampleof B-cells), and by generating V_(HH) sequences directed against OX40L,starting from said sample, using any suitable technique known per se.Such techniques will be clear to the skilled person and/or are furtherdescribed herein.

Alternatively, such naturally occurring V_(HH) domains against OX40L,can be obtained from naïve libraries of Camelid V_(HH) sequences, forexample by screening such a library using OX40L, or at least one part,fragment, antigenic determinant or epitope thereof using one or morescreening techniques known per se. Such libraries and techniques are forexample described in WO 99/37681, WO 01/90190, WO 03/025020 and WO03/035694. Alternatively, improved synthetic or semi-synthetic librariesderived from naïve V_(HH) libraries may be used, such as V_(HH)libraries obtained from naïve V_(HH) libraries by techniques such asrandom mutagenesis and/or CDR shuffling, as for example described in WO00/43507.

Thus, in another aspect, the invention relates to a method forgenerating Nanobodies that are directed against OX40L. In one aspect,said method at least comprises the steps of:

-   a) providing a set, collection or library of Nanobody sequences; and-   b) screening said set, collection or library of Nanobody sequences    for Nanobody sequences that can bind to and/or have affinity for    OX40L;    and-   c) isolating the Nanobody or Nanobodies that can bind to and/or have    affinity for OX40L.

In such a method, the set, collection or library of Nanobody sequencesmay be a naïve set, collection or library of Nanobody sequences; asynthetic or semi-synthetic set, collection or library of Nanobodysequences; and/or a set, collection or library of Nanobody sequencesthat have been subjected to affinity maturation.

In a preferred aspect of this method, the set, collection or library ofNanobody sequences may be an immune set, collection or library ofNanobody sequences, and in particular an immune set, collection orlibrary of V_(HH) sequences, that have been derived from a species ofCamelid that has been suitably immunized with OX40L or with a suitableantigenic determinant based thereon or derived therefrom, such as anantigenic part, fragment, region, domain, loop or other epitope thereof.In one particular aspect, said antigenic determinant may be anextracellular part, region, domain, loop or other extracellularepitope(s).

In the above methods, the set, collection or library of Nanobody orV_(HH) sequences may be displayed on a phage, phagemid, ribosome orsuitable micro-organism (such as yeast), such as to facilitatescreening. Suitable methods, techniques and host organisms fordisplaying and screening (a set, collection or library of) Nanobodysequences will be clear to the person skilled in the art, for example onthe basis of the further disclosure herein. Reference is also made to WO03/054016 and to the review by Hoogenboom in Nature Biotechnology, 23,9, 1105-1116 (2005).

In another aspect, the method for generating Nanobody sequencescomprises at least the steps of:

-   a) providing a collection or sample of cells derived from a species    of Camelid that express immunoglobulin sequences;-   b) screening said collection or sample of cells for (i) cells that    express an immunoglobulin sequence that can bind to and/or have    affinity for OX40L; and (ii) cells that express heavy chain    antibodies, in which substeps (i) and (ii) can be performed    essentially as a single screening step or in any suitable order as    two separate screening steps, so as to provide at least one cell    that expresses a heavy chain antibody that can bind to and/or has    affinity for OX40 L;    and-   c) either (i) isolating from said cell the V_(HH) sequence present    in said heavy chain antibody; or (ii) isolating from said cell a    nucleic acid sequence that encodes the V_(HH) sequence present in    said heavy chain antibody, followed by expressing said V_(HH)    domain.

In the method according to this aspect, the collection or sample ofcells may for example be a collection or sample of B-cells. Also, inthis method, the sample of cells may be derived from a Camelid that hasbeen suitably immunized with OX40L or a suitable antigenic determinantbased thereon or derived therefrom, such as an antigenic part, fragment,region, domain, loop or other epitope thereof. In one particular aspect,said antigenic determinant may be an extracellular part, region, domain,loop or other extracellular epitope(s).

The above method may be performed in any suitable manner, as will beclear to the skilled person. Reference is for example made to EP 0 542810, WO 05/19824, WO 04/051268 and WO 04/106377. The screening of stepb) is preferably performed using a flow cytometry technique such asFACS. For this, reference is for example made to Lieby et al., Blood,Vol. 97, No. 12, 3820. Particular reference is made to the so-called“Nanoclone™” technique described in International application WO06/079372 by Ablynx N.V.

In another aspect, the method for generating an amino acid sequencedirected against OX40L may comprise at least the steps of:

-   a) providing a set, collection or library of nucleic acid sequences    encoding heavy chain antibodies or Nanobody sequences;-   b) screening said set, collection or library of nucleic acid    sequences for nucleic acid sequences that encode a heavy chain    antibody or a Nanobody sequence that can bind to and/or has affinity    for OX40L;    and-   c) isolating said nucleic acid sequence, followed by expressing the    V_(HH) sequence present in said heavy chain antibody or by    expressing said Nanobody sequence, respectively.

In such a method, the set, collection or library of nucleic acidsequences encoding heavy chain antibodies or Nanobody sequences may forexample be a set, collection or library of nucleic acid sequencesencoding a naïve set, collection or library of heavy chain antibodies orV_(HH) sequences; a set, collection or library of nucleic acid sequencesencoding a synthetic or semi-synthetic set, collection or library ofNanobody sequences; and/or a set, collection or library of nucleic acidsequences encoding a set, collection or library of Nanobody sequencesthat have been subjected to affinity maturation.

In a preferred aspect of this method, the set, collection or library ofnucleic acid sequences may be an immune set, collection or library ofnucleic acid sequences encoding heavy chain antibodies or V_(HH)sequences derived from a Camelid that has been suitably immunized withOX40L or with a suitable antigenic determinant based thereon or derivedtherefrom, such as an antigenic part, fragment, region, domain, loop orother epitope thereof. In one particular aspect, said antigenicdeterminant may be an extracellular part, region, domain, loop or otherextracellular epitope(s).

In the above methods, the set, collection or library of nucleotidesequences may be displayed on a phage, phagemid, ribosome or suitablemicro-organism (such as yeast), such as to facilitate screening.Suitable methods, techniques and host organisms for displaying andscreening (a set, collection or library of) nucleotide sequencesencoding amino acid sequences will be clear to the person skilled in theart, for example on the basis of the further disclosure herein.Reference is also made to WO 03/054016 and to the review by Hoogenboomin Nature Biotechnology, 23, 9, 1105-1116 (2005).

As will be clear to the skilled person, the screening step of themethods described herein can also be performed as a selection step.Accordingly the term “screening” as used in the present description cancomprise selection, screening or any suitable combination of selectionand/or screening techniques. Also, when a set, collection or library ofsequences is used, it may contain any suitable number of sequences, suchas 1, 2, 3 or about 5, 10, 50, 100, 500, 1000, 5000, 10⁴, 10⁵, 10⁶, 10⁷,10⁸ or more sequences.

Also, one or more or all of the sequences in the above set, collectionor library of amino acid sequences may be obtained or defined byrational, or semi-empirical approaches such as computer modellingtechniques or biostatics or datamining techniques.

Furthermore, such a set, collection or library can comprise one, two ormore sequences that are variants from one another (e.g. with designedpoint mutations or with randomized positions), compromise multiplesequences derived from a diverse set of naturally diversified sequences(e.g. an immune library)), or any other source of diverse sequences (asdescribed for example in Hoogenboom et al, Nat Biotechnol 23:1105, 2005and Binz et al, Nat Biotechnol 2005, 23:1247). Such set, collection orlibrary of sequences can be displayed on the surface of a phageparticle, a ribosome, a bacterium, a yeast cell, a mammalian cell, andlinked to the nucleotide sequence encoding the amino acid sequencewithin these carriers. This makes such set, collection or libraryamenable to selection procedures to isolate the desired amino acidsequences of the invention. More generally, when a sequence is displayedon a suitable host or host cell, it is also possible (and customary) tofirst isolate from said host or host cell a nucleotide sequence thatencodes the desired sequence, and then to obtain the desired sequence bysuitably expressing said nucleotide sequence in a suitable hostorganism. Again, this can be performed in any suitable manner known perse, as will be clear to the skilled person.

Yet another technique for obtaining V_(HH) sequences or Nanobodysequences directed against OX40L involves suitably immunizing atransgenic mammal that is capable of expressing heavy chain antibodies(i.e. so as to raise an immune response and/or heavy chain antibodiesdirected against OX40L), obtaining a suitable biological sample fromsaid transgenic mammal that contains (nucleic acid sequences encoding)said V_(HH) sequences or Nanobody sequences (such as a blood sample,serum sample or sample of B-cells), and then generating V_(HH) sequencesdirected against OX40L, starting from said sample, using any suitabletechnique known per se (such as any of the methods described herein or ahybridoma technique). For example, for this purpose, the heavy chainantibody-expressing mice and the further methods and techniquesdescribed in WO 02/085945, WO 04/049794 and WO 06/008548 and Janssens etal., Proc. Natl. Acad. Sci. USA. 2006 Oct. 10; 103(41):15130-5 can beused. For example, such heavy chain antibody expressing mice can expressheavy chain antibodies with any suitable (single) variable domain, suchas (single) variable domains from natural sources (e.g. human (single)variable domains, Camelid (single) variable domains or shark (single)variable domains), as well as for example synthetic or semi-synthetic(single) variable domains.

The invention also relates to the V_(HH) sequences or Nanobody sequencesthat are obtained by the above methods, or alternatively by a methodthat comprises the one of the above methods and in addition at least thesteps of determining the nucleotide sequence or amino acid sequence ofsaid V_(HH) sequence or Nanobody sequence; and of expressing orsynthesizing said V_(HH) sequence or Nanobody sequence in a manner knownper se, such as by expression in a suitable host cell or host organismor by chemical synthesis.

As mentioned herein, a particularly preferred class of Nanobodies of theinvention comprises Nanobodies with an amino acid sequence thatcorresponds to the amino acid sequence of a naturally occurring V_(HH)domain, but that has been “humanized”, i.e. by replacing one or moreamino acid residues in the amino acid sequence of said naturallyoccurring V_(HH) sequence (and in particular in the framework sequences)by one or more of the amino acid residues that occur at thecorresponding position(s) in a V_(H) domain from a conventional 4-chainantibody from a human being (e.g. indicated above), as further describedon, and using the techniques mentioned on, page 63 of WO 08/020079.Another particularly preferred class of Nanobodies of the inventioncomprises Nanobodies with an amino acid sequence that corresponds to theamino acid sequence of a naturally occurring V_(H) domain, but that hasbeen “camelized”, i.e. by replacing one or more amino acid residues inthe amino acid sequence of a naturally occurring V_(H) domain from aconventional 4-chain antibody by one or more of the amino acid residuesthat occur at the corresponding position(s) in a V_(HH) domain of aheavy chain antibody, as further described on, and using the techniquesmentioned on, page 63 of WO 08/020079.

Other suitable methods and techniques for obtaining the Nanobodies ofthe invention and/or nucleic acids encoding the same, starting fromnaturally occurring V_(H) sequences or preferably V_(HH) sequences, willbe clear from the skilled person, and may for example include thetechniques that are mentioned on page 64 of WO 08/00279. As mentionedherein, Nanobodies may in particular be characterized by the presence ofone or more “Hallmark residues” (as described herein) in one or more ofthe framework sequences.

Thus, according to one preferred, but non-limiting aspect of theinvention, a Nanobody in its broadest sense can be generally defined asa polypeptide comprising:

-   a) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 108    according to the Kabat numbering is Q;    and/or:-   b) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 45    according to the Kabat numbering is a charged amino acid (as defined    herein) or a cysteine residue, and position 44 is preferably an E;    and/or:-   c) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 103    according to the Kabat numbering is chosen from the group consisting    of P, R and S, and is in particular chosen from the group consisting    of R and S.

Thus, in a first preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which

-   a) the amino acid residue at position 108 according to the Kabat    numbering is Q;    and/or in which:

-   b) the amino acid residue at position 45 according to the Kabat    numbering is a charged amino acid or a cysteine and the amino acid    residue at position 44 according to the Kabat numbering is    preferably E;    and/or in which:

-   c) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of P, R and S, and is    in particular chosen from the group consisting of R and S; and in    which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In particular, a Nanobody in its broadest sense can be generally definedas a polypeptide comprising:

-   a) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 108    according to the Kabat numbering is Q;    and/or:-   b) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 44    according to the Kabat numbering is E and in which the amino acid    residue at position 45 according to the Kabat numbering is an R;    and/or:-   c) an amino acid sequence that is comprised of four framework    regions/sequences interrupted by three complementarity determining    regions/sequences, in which the amino acid residue at position 103    according to the Kabat numbering is chosen from the group consisting    of P, R and S, and is in particular chosen from the group consisting    of R and S.

Thus, according to a preferred, but non-limiting aspect, a Nanobody ofthe invention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which

-   a) the amino acid residue at position 108 according to the Kabat    numbering is Q;    and/or in which:

-   b) the amino acid residue at position 44 according to the Kabat    numbering is E and in which the amino acid residue at position 45    according to the Kabat numbering is an R;    and/or in which:

-   c) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of P, R and S, and is    in particular chosen from the group consisting of R and S; and in    which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In particular, a Nanobody against OX40L according to the invention mayhave the structure:

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which

-   a) the amino acid residue at position 108 according to the Kabat    numbering is Q;    and/or in which:

-   b) the amino acid residue at position 44 according to the Kabat    numbering is E and in which the amino acid residue at position 45    according to the Kabat numbering is an R;    and/or in which:

-   c) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of P, R and S, and is    in particular chosen from the group consisting of R and S; and in    which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In particular, according to one preferred, but non-limiting aspect ofthe invention, a Nanobody can generally be defined as a polypeptidecomprising an amino acid sequence that is comprised of four frameworkregions/sequences interrupted by three complementarity determiningregions/sequences, in which;

-   a-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of A, G, E, D, G, Q,    R, S, L; and is preferably chosen from the group consisting of G, E    or Q; and-   a-2) the amino acid residue at position 45 according to the Kabat    numbering is chosen from the group consisting of L, R or C; and is    preferably chosen from the group consisting of L or R; and-   a-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of W, R or S; and is    preferably W or R, and is most preferably W;-   a-4) the amino acid residue at position 108 according to the Kabat    numbering is Q;    or in which:-   b-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of E and Q; and-   b-2) the amino acid residue at position 45 according to the Kabat    numbering is R; and-   b-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of W, R and S; and is    preferably W;-   b-4) the amino acid residue at position 108 according to the Kabat    numbering is chosen from the group consisting of Q and L; and is    preferably Q;    or in which:-   c-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of A, G, E, D, Q, R, S    and L; and is preferably chosen from the group consisting of G, E    and Q; and-   c-2) the amino acid residue at position 45 according to the Kabat    numbering is chosen from the group consisting of L, R and C; and is    preferably chosen from the group consisting of L and R; and-   c-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of P, R and S; and is    in particular chosen from the group consisting of R and S; and-   c-4) the amino acid residue at position 108 according to the Kabat    numbering is chosen from the group consisting of Q and L; is    preferably Q;    and in which-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

Thus, in another preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   a-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of A, G, E, D, G, Q,    R, S, L; and is preferably chosen from the group consisting of G, E    or Q;    and in which:

-   a-2) the amino acid residue at position 45 according to the Kabat    numbering is chosen from the group consisting of L, R or C; and is    preferably chosen from the group consisting of L or R;    and in which:

-   a-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of W, R or S; and is    preferably W or R, and is most preferably W; and in which

-   a-4) the amino acid residue at position 108 according to the Kabat    numbering is Q;    and in which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In another preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   b-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of E and Q;    and in which:

-   b-2) the amino acid residue at position 45 according to the Kabat    numbering is R; and in which:

-   b-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of W, R and S; and is    preferably W;    and in which:

-   b-4) the amino acid residue at position 108 according to the Kabat    numbering is chosen from the group consisting of Q and L; and is    preferably Q;    and in which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In another preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   c-1) the amino acid residue at position 44 according to the Kabat    numbering is chosen from the group consisting of A, G, E, D, Q, R, S    and L; and is preferably chosen from the group consisting of G, E    and Q;    and in which:

-   c-2) the amino acid residue at position 45 according to the Kabat    numbering is chosen from the group consisting of L, R and C; and is    preferably chosen from the group consisting of L and R;    and in which:

-   c-3) the amino acid residue at position 103 according to the Kabat    numbering is chosen from the group consisting of P, R and S; and is    in particular chosen from the group consisting of R and S;    and in which:

-   c-4) the amino acid residue at position 108 according to the Kabat    numbering is chosen from the group consisting of Q and L; is    preferably Q;    and in which:

-   d) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

Two particularly preferred, but non-limiting groups of the Nanobodies ofthe invention are those according to a) above; according to (a-1) to(a-4) above; according to b) above; according to (b-1) to (b-4) above;according to (c) above; and/or according to (c−1) to (c-4) above, inwhich either:

-   i) the amino acid residues at positions 44-47 according to the Kabat    numbering form the sequence GLEW (or a GLEW-like sequence as    described herein) and the amino acid residue at position 108 is Q;    or in which:-   ii) the amino acid residues at positions 43-46 according to the    Kabat numbering form the sequence KERE or KQRE (or a KERE-like    sequence as described) and the amino acid residue at position 108 is    Q or L, and is preferably Q.

Thus, in another preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   i) the amino acid residues at positions 44-47 according to the Kabat    numbering form the sequence GLEW (or a GLEW-like sequence as defined    herein) and the amino acid residue at position 108 is Q;    and in which:

-   ii) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In another preferred, but non-limiting aspect, a Nanobody of theinvention may have the structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which FR1 to FR4 refer to framework regions 1 to 4,        respectively, and in which CDR1 to CDR3 refer to the        complementarity determining regions 1 to 3, respectively, and in        which:

-   i) the amino acid residues at positions 43-46 according to the Kabat    numbering form the sequence KERE or KQRE (or a KERE-like sequence)    and the amino acid residue at position 108 is Q or L, and is    preferably Q;    and in which:

-   ii) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In the Nanobodies of the invention in which the amino acid residues atpositions 43-46 according to the Kabat numbering form the sequence KEREor KQRE, the amino acid residue at position 37 is most preferably F. Inthe Nanobodies of the invention in which the amino acid residues atpositions 44-47 according to the Kabat numbering form the sequence GLEW,the amino acid residue at position 37 is chosen from the groupconsisting of Y, H, I, L, V or F, and is most preferably V.

Thus, without being limited hereto in any way, on the basis of the aminoacid residues present on the positions mentioned above, the Nanobodiesof the invention can generally be classified on the basis of thefollowing three groups:

-   i) The “GLEW-group”: Nanobodies with the amino acid sequence GLEW at    positions 44-47 according to the Kabat numbering and Q at position    108 according to the Kabat numbering. As further described herein,    Nanobodies within this group usually have a V at position 37, and    can have a W, P, R or S at position 103, and preferably have a W at    position 103. The GLEW group also comprises some GLEW-like sequences    such as those mentioned in Table B-2 below. More generally, and    without limitation, Nanobodies belonging to the GLEW-group can be    defined as Nanobodies with a G at position 44 and/or with a W at    position 47, in which position 46 is usually E and in which    preferably position 45 is not a charged amino acid residue and not    cysteine;-   ii) The “KERE-group”: Nanobodies with the amino acid sequence KERE    or KQRE (or another KERE-like sequence) at positions 43-46 according    to the Kabat numbering and Q or L at position 108 according to the    Kabat numbering. As further described herein, Nanobodies within this    group usually have a F at position 37, an L or F at position 47; and    can have a W, P, R or S at position 103, and preferably have a W at    position 103. More generally, and without limitation, Nanobodies    belonging to the KERE-group can be defined as Nanobodies with a K, Q    or R at position 44 (usually K) in which position 45 is a charged    amino acid residue or cysteine, and position 47 is as further    defined herein;-   iii) The “103 P, R, S-group”: Nanobodies with a P, R or S at    position 103. These Nanobodies can have either the amino acid    sequence GLEW at positions 44-47 according to the Kabat numbering or    the amino acid sequence KERE or KQRE at positions 43-46 according to    the Kabat numbering, the latter most preferably in combination with    an F at position 37 and an L or an F at position 47 (as defined for    the KERE-group); and can have Q or L at position 108 according to    the Kabat numbering, and preferably have Q.

Also, where appropriate, Nanobodies may belong to (i.e. havecharacteristics of) two or more of these classes. For example, onespecifically preferred group of Nanobodies has GLEW or a GLEW-likesequence at positions 44-47; P,R or S (and in particular R) at position103; and Q at position 108 (which may be humanized to L).

More generally, it should be noted that the definitions referred toabove describe and apply to Nanobodies in the form of a native (i.e.non-humanized) V_(HH) sequence, and that humanized variants of theseNanobodies may contain other amino acid residues than those indicatedabove (i.e. one or more humanizing substitutions as defined herein). Forexample, and without limitation, in some humanized Nanobodies of theGLEW-group or the 103 P, R, S-group, Q at position 108 may be humanizedto 108L. As already mentioned herein, other humanizing substitutions(and suitable combinations thereof) will become clear to the skilledperson based on the disclosure herein. In addition, or alternatively,other potentially useful humanizing substitutions can be ascertained bycomparing the sequence of the framework regions of a naturally occurringV_(HH) sequence with the corresponding framework sequence of one or moreclosely related human V_(H) sequences, after which one or more of thepotentially useful humanizing substitutions (or combinations thereof)thus determined can be introduced into said V_(HH) sequence (in anymanner known per se, as further described herein) and the resultinghumanized V_(HH) sequences can be tested for affinity for the target,for stability, for ease and level of expression, and/or for otherdesired properties. In this way, by means of a limited degree of trialand error, other suitable humanizing substitutions (or suitablecombinations thereof) can be determined by the skilled person based onthe disclosure herein. Also, based on the foregoing, (the frameworkregions of) a Nanobody may be partially humanized or fully humanized.

Thus, in another preferred, but non-limiting aspect, a Nanobody of theinvention may be a Nanobody belonging to the GLEW-group (as definedherein), and in which CDR1, CDR2 and CDR3 are as defined herein, and arepreferably as defined according to one of the preferred aspects herein,and are more preferably as defined according to one of the morepreferred aspects herein.

In another preferred, but non-limiting aspect, a Nanobody of theinvention may be a Nanobody belonging to the KERE-group (as definedherein), and CDR1, CDR2 and CDR3 are as defined herein, and arepreferably as defined according to one of the preferred aspects herein,and are more preferably as defined according to one of the morepreferred aspects herein.

Thus, in another preferred, but non-limiting aspect, a Nanobody of theinvention may be a Nanobody belonging to the 103 P, R, S-group (asdefined herein), and in which CDR1, CDR2 and CDR3 are as defined herein,and are preferably as defined according to one of the preferred aspectsherein, and are more preferably as defined according to one of the morepreferred aspects herein.

Also, more generally and in addition to the 1080, 43E/44R and 103 P,R,Sresidues mentioned above, the Nanobodies of the invention can contain,at one or more positions that in a conventional V_(H) domain would form(part of) the V_(H)/V_(L) interface, one or more amino acid residuesthat are more highly charged than the amino acid residues that naturallyoccur at the same position(s) in the corresponding naturally occurringV_(H) sequence, and in particular one or more charged amino acidresidues (as mentioned in Table A-2 on page 48 of the Internationalapplication WO 08/020079). Such substitutions include, but are notlimited to, the GLEW-like sequences mentioned in Table B-2 below; aswell as the substitutions that are described in the InternationalApplication WO 00/29004 for so-called “microbodies”, e.g. so as toobtain a Nanobody with Q at position 108 in combination with KLEW atpositions 44-47. Other possible substitutions at these positions will beclear to the skilled person based upon the disclosure herein.

In one aspect of the Nanobodies of the invention, the amino acid residueat position 83 is chosen from the group consisting of L, M, S, V and W;and is preferably L.

Also, in one aspect of the Nanobodies of the invention, the amino acidresidue at position 83 is chosen from the group consisting of R, K, N,E, G, I, T and Q; and is most preferably either K or E (for Nanobodiescorresponding to naturally occurring V_(HH) domains) or R (for“humanized” Nanobodies, as described herein). The amino acid residue atposition 84 is chosen from the group consisting of P, A, R, S, D T, andV in one aspect, and is most preferably P (for Nanobodies correspondingto naturally occurring V_(HH) domains) or R (for “humanized” Nanobodies,as described herein).

Furthermore, in one aspect of the Nanobodies of the invention, the aminoacid residue at position 104 is chosen from the group consisting of Gand D; and is most preferably G.

Collectively, the amino acid residues at positions 11, 37, 44, 45, 47,83, 84, 103, 104 and 108, which in the Nanobodies are as mentionedabove, will also be referred to herein as the “Hallmark Residues”. TheHallmark Residues and the amino acid residues at the correspondingpositions of the most closely related human V_(H) domain, V_(H)3, aresummarized in Table B-2.

Some especially preferred but non-limiting combinations of theseHallmark Residues as occur in naturally occurring V_(HH) domains arementioned in Table B-3. For comparison, the corresponding amino acidresidues of the human V_(H)3 called DP-47 have been indicated initalics.

TABLE B-2 Hallmark Residues in Nanobodies Position Human V_(H)3 HallmarkResidues  11 L, V; predominantly L L, S, V, M, W, F, T, Q, E, A, R, G,K, Y, N, P, I; preferably L  37 V, I, F; usually V F⁽¹⁾, Y, V, L, A, H,S, I, W, C, N, G, D, T, P, preferably F⁽¹⁾ or Y  44⁽⁸⁾ G E⁽³⁾, Q⁽³⁾,G⁽²⁾, D, A, K, R, L, P, S, V, H, T, N, W, M, I; preferably G⁽²⁾, E⁽³⁾ orQ⁽³⁾; most preferably G⁽²⁾ or Q⁽³⁾  45⁽⁸⁾ L L⁽²⁾, R⁽³⁾, P, H, F, G, Q,S, E, T, Y, C, I, D, V; preferably L⁽²⁾ or R⁽³⁾  47⁽⁸⁾ W, Y F⁽¹⁾, L⁽¹⁾or W⁽²⁾ G, I, S, A, V, M, R, Y, E, P, T, C, H, K, Q, N, D; preferablyW⁽²⁾, L⁽¹⁾ or F⁽¹⁾  83 R or K; usually R R, K⁽⁵⁾, T, E⁽⁵⁾, Q, N, S, I,V, G, M, L, A, D, Y, H; preferably K or R; most preferably K  84 A, T,D; predominantly A P⁽⁵⁾, S, H, L, A, V, I, T, F, D, R, Y, N, Q, G, E;preferably P 103 W W⁽⁴⁾, R⁽⁶⁾, G, S, K, A, M, Y, L, F, T, N, V, Q, P⁽⁶⁾,E, C; preferably W 104 G G, A, S, T, D, P, N, E, C, L; preferably G 108L, M or T; predominantly L Q, L⁽⁷⁾, R, P, E, K, S, T, M, A, H;preferably Q or L⁽⁷⁾ Notes: ⁽¹⁾In particular, but not exclusively, incombination with KERE or KQRE at positions 43-46. ⁽²⁾Usually as GLEW atpositions 44-47. ⁽³⁾Usually as KERE or KQRE at positions 43-46, e.g. asKEREL, KEREF, KQREL, KQREF, KEREG, KQREW or KQREG at positions 43-47.Alternatively, also sequences such as TERE (for example TEREL), TQRE(for example TQREL), KECE (for example KECEL or KECER), KQCE (forexample KQCEL), RERE (for example REREG), RQRE (for example RQREL, RQREFor RQREW), QERE (for example QEREG), QQRE, (for example QQREW, QQREL orQQREF), KGRE (for example KGREG), KDRE (for example KDREV) are possible.Some other possible, but less preferred sequences include for exampleDECKL and NVCEL. ⁽⁴⁾With both GLEW at positions 44-47 and KERE or KQREat positions 43-46. ⁽⁵⁾Often as KP or EP at positions 83-84 of naturallyoccurring V_(HH) domains. ⁽⁶⁾In particular, but not exclusively, incombination with GLEW at positions 44-47. ⁽⁷⁾With the proviso that whenpositions 44-47 are GLEW, position 108 is always Q in (non-humanized)V_(HH) sequences that also contain a W at 103. ⁽⁸⁾The GLEW group alsocontains GLEW-like sequences at positions 44-47, such as for exampleGVEW, EPEW, GLER, DQEW, DLEW, GIEW, ELEW, GPEW, EWLP, GPER, GLER andELEW.

TABLE B-3 Some preferred but non-limiting combinations of HallmarkResidues in naturally occurring Nanobodies. For humanization of thesecombinations, reference is made to the specification. 11 37 44 45 47 8384 103 104 108 DP-47 (human) M V G L W R A W G L “KERE” group L F E R LK P w G Q L F E R F E P W G Q L F E R F K P W G Q L Y Q R L K P W G Q LF L R V K P Q G Q L F Q R L K P W G Q L F E R F K P W G Q “GLEW” group LV G L W K S W G Q M V G L W K P R G Q

In the Nanobodies, each amino acid residue at any other position thanthe Hallmark Residues can be any amino acid residue that naturallyoccurs at the corresponding position (according to the Kabat numbering)of a naturally occurring V_(HH) domain.

Such amino acid residues will be clear to the skilled person. Tables B-4to B-7 mention some non-limiting residues that can be present at eachposition (according to the Kabat numbering) of the FR1, FR2, FR3 and FR4of naturally occurring V_(HH) domains. For each position, the amino acidresidue that most frequently occurs at each position of a naturallyoccurring V_(HH) domain (and which is the most preferred amino acidresidue for said position in a Nanobody) is indicated in bold; and otherpreferred amino acid residues for each position have been underlined(note: the number of amino acid residues that are found at positions26-30 of naturally occurring V_(HH) domains supports the hypothesisunderlying the numbering by Chothia (supra) that the residues at thesepositions already form part of CDR1).

In Tables B-4-B-7, some of the non-limiting residues that can be presentat each position of a human V_(H)3 domain have also been mentioned.Again, for each position, the amino acid residue that most frequentlyoccurs at each position of a naturally occurring human V_(H)3 domain isindicated in bold; and other preferred amino acid residues have beenunderlined.

For reference only, Tables B-4-B-7 also contain data on the V_(HH)entropy (“V_(HH) Ent.”) and V_(HH) variability (“V_(HH) Var.”) at eachamino acid position for a representative sample of 7732 V_(HH) sequences(including a.o. data kindly provided by David Lutje Hulsing and Prof.Theo Verrips of Utrecht University). The values for the V_(HH) entropyand the V_(HH) variability provide a measure for the variability anddegree of conservation of amino acid residues between the 7732 V_(HH)sequences analyzed: low values (i.e. <1, such as <0.5) indicate that anamino acid residue is highly conserved between the V_(HH) sequences(i.e. little variability). For example, the G at position 9 and the W atposition 36 have values for the V_(HH) entropy of 0.01 and 0respectively, indicating that these residues are highly conserved andhave little variability (and in case of position 36 is W in all 7732sequences analysed), whereas for residues that form part of the CDR'sgenerally values of 1.5 or more are found (data not shown). Note thatthe data represented below support the hypothesis that the amino acidresidues at positions 27-30 and maybe even also at positions 93 and 94already form part of the CDR's (although the invention is not limited toany specific hypothesis or explanation, and as mentioned above, hereinthe numbering according to Kabat is used). For a general explanation ofsequence entropy, sequence variability and the methodology fordetermining the same, see Oliveira et al., PROTEINS:Structure, Functionand Genetics, 52: 544-552 (2003).

TABLE B-4 Non-limiting examples of amino acid residues in FR1 (for thefootnotes, see the footnotes to Table B-2) Amino acid residue(s): V_(HH)V_(HH) Pos. Human V_(H)3 Camelid V_(HH)'s Ent. Var. 1 E, Q E, Q, K, D,A, G, R 0.47 5 2 V V, M, A, E, L 0.04 1 3 Q Q, K, P, H, F, R 0.04 1 4 LL, M, Q, P, R, F, V 0.02 1 5 V, L V, Q, M, E, A, L, P, K, R 0.35 3 6 EE, A, Q, D, K, H 0.21 5 7 S,T S, F, L, W, T 0.05 2 8 G, R G, R, E, V0.04 1 9 G G, R, V, A 0.01 1 10 G, V G, D, R, S, K, E, A, Q, N, T, V0.22 4 11 Hallmark residue: L, S, V, M, W, F, T, Q, E, A, R, G, K, Y, N,P, I; 0.35 4 preferably L 12 V, I V, A, L, M, E, G, T 0.11 2 13 Q, K, RQ, L, R, H, P, E, K, T, S, V, D, G, A, N, M 0.46 3 14 P A, P, T, V, S,D, F, N, I, E, L, R, G, Y, Q, H 0.92 5 15 G G, E 0 1 16 G, R G, D, E, A,S, N, V, R, K, T, P, C, L 0.47 4 17 S S, F, P, Y, T, A, C, R, N 0.14 218 L L, V, R, M, P, Q, S, A, T, K, H 0.06 1 19 R, K R, T, K, S, N, G, A,I, L, Q, F, E, V, M 0.36 4 20 L L, F, V, I, P, H, S 0.18 3 21 S S, A, T,P, F, V, H, D, R, L, I, G 0.13 3 22 C C, W 0 1 23 A, T A, V, T, E, S, L,G, I, K, Q, R, D, F, N, P, M 0.88 5 24 A A, D, V, T, H, Y, P, G, S, F,L, I, N, Q, E, R 0.78 9 25 S S, P, T, A, F, L, N, Y, R, H, D, V, I, W,G, K, Q, C 0.2 2 26 G G, E, R, V, T, A, S, K, D, L, I, Q, N, F, Y, M, W,P, H 0.45 6 27 F R, F, S, P, L, G, I, N, T, D, H, V, E, A, Y, K, M, Q,W, C 1.89 12 28 T T, I, S, A, P, F, D, N, V, R, M, L, G, Y, K, E, H, W,Q 1.29 12 29 F, V F, L, S, V, I, A, W, Y, G, D, R, T, P, N, E, M, H, Q,K, C 1.23 11 30 S, D, G S, D, N, G, R, T, A, E, I, Y, K, V, H, L, F, W,M, P, C, Q 1.55 12

TABLE B-5 Non-limiting examples of amino acid residues in FR2 (for thefootnotes, see the footnotes to Table B-2) Amino acid residue(s): V_(HH)V_(HH) Pos. Human V_(H)3 Camelid V_(HH)'s Ent. Var.  36 W W 0 1 37Hallmark residue: F⁽¹⁾, Y, V, L, A, H, S, I, W, C, N, G, D, T, P, 1.1 7preferably F⁽¹⁾or Y 38 R R, H, C, P, Y, L, V 0.01 1 39 Q Q, E, R, H, L,A, S, K, P, V, T, D 0.22 3 40 A A, V, T, P, G, S, D, I, L, R, N, F, Y,C, E, H 0.55 6 41 P, S, T P, S, A, L, T, Q, R, V, D, G, I, H 0.18 3 42 GG, E, A, R, D, V, W, T, Q, K, L, N, H, M 0.1 2 43 K K, N, Q, E, R, T, L,S, M, D, G, A, V, H, 1, F, P 0.45 7 44 Hallmark residue: E⁽³⁾, Q⁽³⁾,G⁽²⁾, D, A, K, R, L, P, S, V, H, T, 1.11 4 N, W, M, I; preferably G⁽²⁾,E⁽³⁾or Q⁽³⁾; most preferably G⁽²⁾ or Q⁽³⁾ 45 Hallmark residue: L⁽²⁾,R⁽³⁾, P, H, F, G, Q, S, E, T, Y, C, I, 0.56 3 D, V; preferablyL^((2) or R) ⁽³⁾ 46 E, V E, D, A, Q, V, M, K, T, G, R, S, N, I, L, F0.42 4 47 Hallmark residue: F⁽¹⁾, L⁽¹⁾ or W⁽²⁾ G, I, S, A, V, M, R, Y,1.64 11 E, P, T, C, H, K, Q, N, D; preferably W⁽²⁾, L⁽¹⁾ or F⁽¹⁾ 48 V V,I, L, A, T, Q, F, M, G, E, R 0.35 5 49 S, A, G A, S, G, T, V, L, C, I,F, P, E, Y, M, D, R 0.89 5

TABLE B-6 Non-limiting examples of amino acid residues in FR3 (for thefootnotes, see the footnotes to Table B-2) Amino acid residue(s): V_(HH)V_(HH) Pos. Human V_(H)3 Camelid V_(HH)'s Ent. Var. 66 R R 0 1 67 F F,S, L, V, I, C, A, Y, M, G 0.1 1 68 T T, A, S, I, F, V, P, N, G, R, K, M,D, L, W, Q 0.34 4 69 I I, V, M, T, L, A, F, P, S, G, N 0.5 5 70 S S, T,A, F, P, V, Y, L, D, G, N, H, W, E, C 0.22 4 71 R R, S, K, G, T, I, W,A, N, V, E, L, M, F, D, Q, C 0.61 7 72 D, E D, N, E, G, V, A, H, L, S,T, I, Q, F, P, Y, R 0.34 4 73 N, D, G N, D, S, K, I, Y, G, T, H, R, A,V, F, L, E, M, P, C 0.65 9 74 A, S A, T, V, S, F, G, D, P, N, I, R, L,Y, H, E, Q, K, W, M 0.8 8 75 K K, N, E, R, Q, A, G, T, M, S, L, D, V, W,Y, I 0.71 6 76 N, S N, K, S, R, D, T, H, G, E, A, Y, I, M, Q, L, W, P,F, V 0.66 7 77 S, T, I T, A, M, S, R, I, V, L, P, E, N, K, G, W, Q 0.727 78 L, A V, L, A, M, I, G, T, F, W, Q, S, E, N, H 1.11 6 79 Y, H Y, F,D, S, H, N, T, A, L, W, V, C, G, E, I, P, R 0.68 8 80 L L, M, V, P, F0.05 2 81 Q Q, E, R, H, L, D, T, G, K, P, A, I, S, N, Y, V, M 0.38 4 82M M, I, L, V, A, T, S, K 0.12 3 82a N, G N, S, D, T, E, H, K, I, A, G,R, Y, L, V, F, Q 0.77 5 82b S S, N, T, G, H, D, R, A, K, I, M, V, F, E,P, Y, C, L 0.72 8 82c L L, V, M, P, A, T, G 0.08 2 83 Hallmark residue:R, K⁽⁵⁾, T, E⁽⁵⁾, Q, N, S, I, V, G, M, L, A, D, Y, H; preferably 0.66 6K or R; most preferably K 84 Hallmark residue: P⁽⁵⁾, S, H, L, A, V, I,T, F, D, R, Y, N, Q, G, E; preferably P 0.85 7 85 E, G E, D, G, A, Q, V,S, N, K, T, R, L 0.27 3 86 D D, E, G, N 0.02 1 87 T, M T, S, A, M, R, P,K, E 0.15 3 88 A A, G, S, D, N, T, P, V 0.23 2 89 V, L V, I, L, E, A, R,T, D, F, M, N, S, K, G, Q, H 0.71 7 90 Y Y, H, F, N 0 1 91 Y, H Y, F, R,S, H, T, I, V, L, N, D, C, Q, W, A, E, M 0.6 7 92 C C, R, P 0 1 93 A, K,T A, N, T, K, G, V, R, Y, S, H, W, L, F, Q, M, I, E, C, D 1.33 10 94 K,R, T A, K, V, T, R, L, G, S, D, Q, I, M, F, Y, N, E, H, P, C, W 1.55 12

TABLE B-7 Non-limiting examples of amino acid residues in FR4 (for thefootnotes, see the footnotes to Table B-2) Amino acid residue(s): V_(HH)V_(HH) Pos. Human V_(H)3 Camelid V_(HH)'s Ent. Var. 103 Hallmarkresidue: W⁽⁴⁾, R⁽⁶⁾, 0.54 6 G, S, K, A, M, Y, L, F, T, N, V, Q, P⁽⁶⁾, E,C; preferably W 104 Hallmark residue: G, A, S, T, D, P, N, E, C, L; 0.133 preferably G 105 Q, R Q, K, H, R, P, E, L, T, N, S, 0.52 5 V, A, M, G106 G G, R, E 0 1 107 T T, Q, I, A, S, N, R, V, D 0.24 3 108 Hallmarkresidue: Q, L⁽⁷⁾, R, P, 0.3 4 E, K, S, T, M, A, H; preferably Q or L⁽⁷⁾109 V V, I, L 0 1 110 T T, S, N, A, I, F 0.01 1 111 V V, I, A 0.01 1 112S S, T, P, F, A 0.01 1 113 S S, T, A, L, P, F, E, V 0.04 1

Thus, in another preferred, but not limiting aspect, a Nanobody of theinvention can be defined as an amino acid sequence with the (general)structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4

in which FR1 to FR4 refer to framework regions 1 to 4, respectively, andin which CDR1 to CDR3 refer to the complementarity determining regions 1to 3, respectively, and in which:

-   i) one or more of the amino acid residues at positions 11, 37, 44,    45, 47, 83, 84, 103, 104 and 108 according to the Kabat numbering    are chosen from the Hallmark residues mentioned in Table B-2;    and in which:-   ii) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

The above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein.

In particular, a Nanobody of the invention can be an amino acid sequencewith the (general) structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4

in which FR1 to FR4 refer to framework regions 1 to 4, respectively, andin which CDR1 to CDR3 refer to the complementarity determining regions 1to 3, respectively, and in which:

-   i) (preferably) one or more of the amino acid residues at positions    11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according to the Kabat    numbering are chosen from the Hallmark residues mentioned in Table    B-2 (it being understood that V_(HH) sequences will contain one or    more Hallmark residues; and that partially humanized Nanobodies will    usually, and preferably, [still] contain one or more Hallmark    residues [although it is also within the scope of the invention to    provide—where suitable in accordance with the invention—partially    humanized Nanobodies in which all Hallmark residues, but not one or    more of the other amino acid residues, have been humanized]; and    that in fully humanized Nanobodies, where suitable in accordance    with the invention, all amino acid residues at the positions of the    Hallmark residues will be amino acid residues that occur in a human    V_(H)3 sequence. As will be clear to the skilled person based on the    disclosure herein that such V_(HH) sequences, such partially    humanized Nanobodies with at least one Hallmark residue, such    partially humanized Nanobodies without Hallmark residues and such    fully humanized Nanobodies all form aspects of this invention);    and in which:-   ii) said amino acid sequence has at least 80% amino acid identity    with at least one of the amino acid sequences of SEQ ID NO's: 1 to    22, in which for the purposes of determining the degree of amino    acid identity, the amino acid residues that form the CDR sequences    (indicated with X in the sequences of SEQ ID NO's: 1 to 22) are    disregarded;    and in which:-   iii) CDR1, CDR2 and CDR3 are as defined herein, and are preferably    as defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

The above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein.

TABLE B-8 Representative amino acid sequences for Nanobodies of the KERE, GLEW and P,R,S 103group. The CDR's are indicated with XXXXX KERE sequence SEQ ID NO: 1EVQLVESGGGLVQPGGSLRLSCAASGIPFSXXXX no. 1XWFRQAPGKQRDSVAXXXXXRFTISRDNAKNTVY LQMNSLKPEDTAVYRCYFXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 2 QVKLEESGGGLVQAGGSLRLSCVGSGRTFSXXXX no. 2XWFRLAPGKEREFVAXXXXXRFTISRDTASNRGY LHMNNLTPEDTAVYYCAAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 3 AVQLVDSGGGLVQAGDSLKLSCALTGGAFTXXXX no. 3XWFRQTPGREREFVAXXXXXRFTISRDNAKNMVY LRMNSLIPEDAAVYSCAAXXXXXWGQGTLVTVSSKERE sequence SEQ ID NO: 4 QVQLVESGGGLVEAGGSLRLSCTASESPFRXXXX no. 4XWFRQTSGQEREFVAXXXXXRFTISRDDAKNTVW LHGSTLKPEDTAVYYCAAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 5 AVQLVESGGGLVQGGGSLRLACAASERIFDXXXX no. 5XWYRQGPGNERELVAXXXXXRFTISMDYTKQTVY LHMNSLRPEDTGLYYCKIXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 6 DVKFVESGGGLVQAGGSLRLSCVASGFNFDXXXX no. 6XWFRQAPGKEREEVAXXXXXRFTISSEKDKNSVY LQMNSLKPEDTALYICAGXXXXXWGRGTQVTVSSKERE sequence SEQ ID NO: 7 QVRLAESGGGLVQSGGSLRLSCVASGSTYTXXXX no. 7XWYRQYPGKQRALVAXXXXXRFTIARDSTKDTFC LQMNNLKPEDTAVYYCYAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 8 EVQLVESGGGLVQAGGSLRLSCAASGFTSDXXXX no. 8XWFRQAPGKPREGVSXXXXXRFTISTDNAKNTVH LLMNRVNAEDTALYYCAVXXXXXWGRGTRVTVSSKERE sequence SEQ ID NO: 9 QVQLVESGGGLVQPGGSLRLSCQASGDISTXXXX no. 9XWYRQVPGKLREFVAXXXXXRFTISGDNAKRAIY LQMNNLKPDDTAVYYCNRXXXXXWGQGTQVTVSPKERE sequence SEQ ID NO: 10 QVPVVESGGGLVQAGDSLRLFCAVPSFTSTXXXX no. 10XWFRQAPGKEREFVAXXXXXRFTISRNATKNTLT LRMDSLKPEDTAVYYCAAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 11 EVQLVESGGGLVQAGDSLRLFCTVSGGTASXXXX no. 11XWFRQAPGEKREFVAXXXXXRFTIARENAGNMVY LQMNNLKPDDTALYTCAAXXXXXWGRGTQVTVSSKERE sequence SEQ ID NO: 12 AVQLVESGGDSVQPGDSQTLSCAASGRTNSXXXX no. 12XWFRQAPGKERVFLAXXXXXRFTISRDSAKNMMY LQMNNLKPQDTAVYYCAAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 13 AVQLVESGGGLVQAGGSLRLSCVVSGLTSSXXXX no. 13XWFRQTPWQERDFVAXXXXXRFTISRDNYKDTVL LEMNFLKPEDTAIYYCAAXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 14 AVQLVESGGGLVQAGASLRLSCATSTRTLDXXXX no. 14XWFRQAPGRDREFVAXXXXXRFTVSRDSAENTVA LQMNSLKPEDTAVYYCAAXXXXXWGQGTRVTVSSKERE sequence SEQ ID NO: 15 QVQLVESGGGLVQPGGSLRLSCTVSRLTAHXXXX no. 15XWFRQAPGKEREAVSXXXXXRFTISRDYAGNTAF LQMDSLKPEDTGVYYCATXXXXXWGQGTQVTVSSKERE sequence SEQ ID NO: 16 EVQLVESGGELVQAGGSLKLSCTASGRNFVXXXX no. 16XWFRRAPGKEREFVAXXXXXRFTVSRDNGKNTAY LRMNSLKPEDTADYYCAVXXXXXLGSGTQVTVSSGLEW sequence SEQ ID NO: 17 AVQLVESGGGLVQPGGSLRLSCAASGFTFSXXXX no. 1XWVRQAPGKVLEWVSXXXXXRFTISRDNAKNTLY LQMNSLKPEDTAVYYCVKXXXXXGSQGTQVTVSSGLEW sequence SEQ ID NO: 18 EVQLVESGGGLVQPGGSLRLSCVCVSSGCTXXXX no. 2XWVRQAPGKAEEWVSXXXXXRFKISRDNAKKTLY LQMNSLGPEDTAMYYCQRXXXXXRGQGTQVTVSSGLEW sequence SEQ ID NO: 19 EVQLVESGGGLALPGGSLTLSCVFSGSTFSXXXX no. 3XWVRHTPGKAEEWVSXXXXXRFTISRDNAKNTLY LEMNSLSPEDTAMYYCGRXXXXXRSKGIQVTVSSP,R,S 103 SEQ ID NO: 20 AVQLVESGGGLVQAGGSLRLSCAASGRTFSXXXXsequence no. 1 XWFRQAPGKEREFVAXXXXXRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAXXXXXRGQGTQVTVSS P,R,S 103 SEQ ID NO: 21DVQLVESGGDLVQPGGSLRLSCAASGFSFDXXXX sequence no. 2XWLRQTPGKGLEWVGXXXXXRFTISRDNAKNMLY LHLNNLKSEDTAVYYCRRXXXXXLGQGTQVTVSSP,R,S 103 SEQ ID NO: 22 EVQLVESGGGLVQPGGSLRLSCVCVSSGCTXXXXsequence no. 3 XWVRQAPGKAEEWVSXXXXXRFKISRDNAKKTLYLQMNSLGPEDTAMYYCQRXXXXXRGQGTQVTVSS

In particular, a Nanobody of the invention of the KERE group can be anamino acid sequence with the (general) structure

-   -   FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4        in which:

-   i) the amino acid residue at position 45 according to the Kabat    numbering is a charged amino acid (as defined herein) or a cysteine    residue, and position 44 is preferably an E;    and in which:

-   ii) FR1 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-9 Representative FW1 sequences for Nanobodies of the KERE-group.KERE FW1 SEQ ID NO: 23 QVQRVESGGGLVQAG sequence no. 1 GSLRLSCAASGRTSSKERE FW1 SEQ ID NO: 24 QVQLVESGGGLVQTG sequence no. 2 DSLSLSCSASGRTFSKERE FW1 SEQ ID NO: 25 QVKLEESGGGLVQAG sequence no. 3 DSLRLSCAATGRAFGKERE FW1 SEQ ID NO: 26 AVQLVESGGGLVQPG sequence no. 4 ESLGLSCVASGRDFVKERE FW1 SEQ ID NO: 27 EVQLVESGGGLVQAG sequence no. 5 GSLRLSCEVLGRTAGKERE FW1 SEQ ID NO: 28 QVQLVESGGGWVQPG sequence no. 6 GSLRLSCAASETILSKERE FW1 SEQ ID NO: 29 QVQLVESGGGTVQPG sequence no. 7 GSLNLSCVASGNTFNKERE FW1 SEQ ID NO: 30 EVQLVESGGGLAQPG sequence no. 8 GSLQLSCSAPGFTLDKERE FW1 SEQ ID NO: 31 AQELEESGGGLVQAG sequence no. 9 GSLRLSCAASGRTFNand in which:

-   iii) FR2 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-10 Representative FW2 sequencesfor Nanobodies of the KERE-group. KERE FW2 SEQ ID NO: 41 WFRQAPGKEREFVAsequence no. 1 KERE FW2 SEQ ID NO: 42 WFRQTPGREREFVA sequence no. 2KERE FW2 SEQ ID NO: 43 WYRQAPGKQREMVA sequence no. 3 KERE FW2SEQ ID NO: 44 WYRQGPGKQRELVA sequence no. 4 KERE FW2 SEQ ID NO: 45WIRQAPGKEREGVS sequence no. 5 KERE FW2 SEQ ID NO: 46 WFREAPGKEREGISsequence no. 6 KERE FW2 SEQ ID NO: 47 WYRQAPGKERDLVA sequence no. 7KERE FW2 SEQ ID NO: 48 WFRQAPGKQREEVS sequence no. 8 KERE FW2SEQ ID NO: 49 WFRQPPGKVREFVG sequence no. 9and in which:

-   iv) FR3 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-11 Representative FW3 sequencesfor Nanobodies of the KERE-group. KERE FW3 SEQ ID NO: 50RFTISRDNAKNTVYLQ sequence no. 1 MNSLKPEDTAVYRCYF KERE FW3 SEQ ID NO: 51RFAISRDNNKNTGYLQ sequence no. 2 MNSLEPEDTAVYYCAA KERE FW3 SEQ ID NO: 52RFTVARNNAKNTVNLE sequence no. 3 MNSLKPEDTAVYYCAA KERE FW3 SEQ ID NO: 53RFTISRDIAKNTVDLL sequence no. 4 MNNLEPEDTAVYYCAA KERE FW3 SEQ ID NO: 54RLTISRDNAVDTMYLQ sequence no. 5 MNSLKPEDTAVYYCAA KERE FW3 SEQ ID NO: 55RFTISRDNAKNTVYLQ sequence no. 6 MDNVKPEDTAIYYCAA KERE FW3 SEQ ID NO: 56RFTISKDSGKNTVYLQ sequence no. 7 MTSLKPEDTAVYYCAT KERE FW3 SEQ ID NO: 57RFTISRDSAKNMMYLQ sequence no. 8 MNNLKPQDTAVYYCAA KERE FW3 SEQ ID NO: 58RFTISRENDKSTVYLQ sequence no. 9 LNSLKPEDTAVYYCAA KERE FW3 SEQ ID NO: 59RFTISRDYAGNTAYLQ sequence no. 10 MNSLKPEDTGVYYCATand in which:

-   v) FR4 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-12 Representative FW4 sequencesfor Nanobodies of the KERE-group. KERE FW4 SEQ ID NO: 60 WGQGTQVTVSSsequence no. 1 KERE FW4 SEQ ID NO: 61 WGKGTLVTVSS sequence no. 2KERE FW4 SEQ ID NO: 62 RGQGTRVTVSS sequence no. 3 KERE FW4 SEQ ID NO: 63WGLGTQVTISS sequence no. 4and in which:

-   vi) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In the above Nanobodies, one or more of the further Hallmark residuesare preferably as described herein (for example, when they are V_(HH)sequences or partially humanized Nanobodies).

Also, the above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein.

With regard to framework 1, it will be clear to the skilled person that,when an amino acid sequence as outlined above is generated by expressionof a nucleotide sequence, the first four amino acid sequences (i.e.amino acid residues 1-4 according to the Kabat numbering) may often bedetermined by the primer(s) that have been used to generate said nucleicacid. Thus, for determining the degree of amino acid identity, the firstfour amino acid residues are preferably disregarded.

Also, with regard to framework 1, and although amino acid positions 27to 30 are according to the Kabat numbering considered to be part of theframework regions (and not the CDR's), it has been found by analysis ofa database of more than 1000 V_(HH) sequences that the positions 27 to30 have a variability (expressed in terms of V_(HH) entropy and V_(HH)variability—see Tables B-4 to B-7) that is much greater than thevariability on positions 1 to 26. Because of this, for determining thedegree of amino acid identity, the amino acid residues at positions 27to 30 are preferably also disregarded.

In view of this, a Nanobody of the KERE class may be an amino acidsequence that is comprised of four framework regions/sequencesinterrupted by three complementarity determining regions/sequences, inwhich:

-   i) the amino acid residue at position 45 according to the Kabat    numbering is a charged amino acid (as defined herein) or a cysteine    residue, and position 44 is preferably an E; and in which:-   ii) FR1 is an amino acid sequence that, on positions 5 to 26 of the    Kabat numbering, has at least 80% amino acid identity with at least    one of the following amino acid sequences:

TABLE B-13 Representative FW1 sequences (amino acid residues 5 to 26)for Nanobodies of the KERE-group. KERE FW1 SEQ ID NO: 32 VESGGGLVQPGsequence no. 10 GSLRLSCAASG KERE FW1 SEQ ID NO: 33 VDSGGGLVQAGsequence no. 11 DSLKLSCALTG KERE FW1 SEQ ID NO: 34 VDSGGGLVQAGsequence no. 12 DSLRLSCAASG KERE FW1 SEQ ID NO: 35 VDSGGGLVEAGsequence no. 13 GSLRLSCQVSE KERE FW1 SEQ ID NO: 36 QDSGGGSVQAGsequence no. 14 GSLKLSCAASG KERE FW1 SEQ ID NO: 37 VQSGGRLVQAGsequence no. 15 DSLRLSCAASE KERE FW1 SEQ ID NO: 38 VESGGTLVQSGsequence no. 16 DSLKLSCASST KERE FW1 SEQ ID NO: 39 MESGGDSVQSGsequence no. 17 GSLTLSCVASG KERE FW1 SEQ ID NO: 40 QASGGGLVQAGsequence no. 18 GSLRLSCSASVand in which:

-   iii) FR2, FR3 and FR4 are as mentioned herein for FR2, FR3 and FR4    of Nanobodies of the KERE-class;    and in which:-   iv) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

The above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein.

A Nanobody of the GLEW class may be an amino acid sequence that iscomprised of four framework regions/sequences interrupted by threecomplementarity determining regions/sequences, in which

-   i) preferably, when the Nanobody of the GLEW-class is a    non-humanized Nanobody, the amino acid residue in position 108 is Q;-   ii) FR1 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-14 Representative FW1 sequencesfor Nanobodies of the GLEW-group. GLEW FW1 SEQ ID NO: 64 QVQLVESGGGLVQPGsequence no. 1 GSLRLSCAASGFTFS GLEW FW1 SEQ ID NO: 65 EVHLVESGGGLVRPGsequence no. 2 GSLRLSCAAFGFIFK GLEW FW1 SEQ ID NO: 66 QVKLEESGGGLAQPGsequence no. 3 GSLRLSCVASGFTFS GLEW FW1 SEQ ID NO: 67 EVQLVESGGGLVQPGsequence no. 4 GSLRLSCVCVSSGCT GLEW FW1 SEQ ID NO: 68 EVQLVESGGGLALPGsequence no. 5 GSLTLSCVFSGSTFSand in which:

-   iii) FR2 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-15 Representative FW2 sequencesfor Nanobodies of the GLEW-group. GLEW FW2 SEQ ID NO: 72 WVRQAPGKVLEWVSsequence no. 1 GLEW FW2 SEQ ID NO: 73 WVRRPPGKGLEWVS sequence no. 2GLEW FW2 SEQ ID NO: 74 WVRQAPGMGLEWVS sequence no. 3 GLEW FW2SEQ ID NO: 75 WVRQAPGKEPEWVS sequence no. 4 GLEW FW2 SEQ ID NO: 76WVRQAPGKDQEWVS sequence no. 5 GLEW FW2 SEQ ID NO: 77 WVRQAPGKAEEWVSsequence no. 6 GLEW FW2 SEQ ID NO: 78 WVRQAPGKGLEWVA sequence no. 7GLEW FW2 SEQ ID NO: 79 WVRQAPGRATEWVS sequence no. 8and in which:

-   iv) FR3 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-16 Representative FW3 sequencesfor Nanobodies of the GLEW-group. GLEW FW3 SEQ ID NO: 80RFTISRDNAKNTLYLQ sequence no. 1 MNSLKPEDTAVYYCVK GLEW FW3 SEQ ID NO: 81RFTISRDNARNTLYLQ sequence no. 2 MDSLIPEDTALYYCAR GLEW FW3 SEQ ID NO: 82RFTSSRDNAKSTLYLQ sequence no. 3 MNDLKPEDTALYYCAR GLEW FW3 SEQ ID NO: 83RFIISRDNAKNTLYLQ sequence no. 4 MNSLGPEDTAMYYCQR GLEW FW3 SEQ ID NO: 84RFTASRDNAKNTLYLQ sequence no. 5 MNSLKSEDTARYYCAR GLEW FW3 SEQ ID NO: 85RFTISRDNAKNTLYLQ sequence no. 6 MDDLQSEDTAMYYCGRand in which:

-   v) FR4 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-17 Representative FW4 sequencesfor Nanobodies of the GLEW-group. GLEW FW4 SEQ ID NO: 86 GSQGTQVTVSSsequence no. 1 GLEW FW4 SEQ ID NO: 87 LRGGTQVTVSS sequence no. 2GLEW FW4 SEQ ID NO: 88 RGQGTLVTVSS sequence no. 3 GLEW FW4 SEQ ID NO: 89RSRGIQVTVSS sequence no. 4 GLEW FW4 SEQ ID NO: 90 WGKGTQVTVSSsequence no. 5 GLEW FW4 SEQ ID NO: 91 WGQGTQVTVSS sequence no. 6and in which:

-   vi) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In the above Nanobodies, one or more of the further Hallmark residuesare preferably as described herein (for example, when they are V_(HH)sequences or partially humanized Nanobodies).

With regard to framework 1, it will again be clear to the skilled personthat, for determining the degree of amino acid identity, the amino acidresidues on positions 1 to 4 and 27 to 30 are preferably disregarded.

In view of this, a Nanobody of the GLEW class may be an amino acidsequence that is comprised of four framework regions/sequencesinterrupted by three complementarity determining regions/sequences, inwhich:

-   i) preferably, when the Nanobody of the GLEW-class is a    non-humanized Nanobody, the amino acid residue in position 108 is Q;    and in which:-   ii) FR1 is an amino acid sequence that, on positions 5 to 26 of the    Kabat numbering, has at least 80% amino acid identity with at least    one of the following amino acid sequences:

TABLE B-18 Representative FW1 sequences(amino acid residues 5 to 26) for Nanobodies of the KERE-group. GLEW FW1SEQ ID NO: 69 VESGGGLVQPG sequence no. 6 GSLRLSCAASG GLEW FW1SEQ ID NO: 70 EESGGGLAQPG sequence no. 7 GSLRLSCVASG GLEW FW1SEQ ID NO: 71 VESGGGLALPG sequence no. 8 GSLTLSCVFSGand in which:

-   iii) FR2, FR3 and FR4 are as mentioned herein for FR2, FR3 and FR4    of Nanobodies of the GLEW-class;    and in which:-   iv) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

The above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein. Inthe above Nanobodies, one or more of the further Hallmark residues arepreferably as described herein (for example, when they are V_(HH)sequences or partially humanized Nanobodies).

A Nanobody of the P, R, S 103 class may be an amino acid sequence thatis comprised of four framework regions/sequences interrupted by threecomplementarity determining regions/sequences, in which

-   i) the amino acid residue at position 103 according to the Kabat    numbering is different from W;    and in which:-   ii) preferably the amino acid residue at position 103 according to    the Kabat numbering is P, R or S, and more preferably R;    and in which:-   iii) FR1 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-19 Representative FW1 sequences forNanobodies of the P,R,S 103-group. P,R,S 103 FW1 SEQ ID NO: 92AVQLVESGGGLVQAG sequence no. 1 GSLRLSCAASGRTFS P,R,S 103 FW1SEQ ID NO: 93 QVQLQESGGGMVQPG sequence no. 2 GSLRLSCAASGFDFGP,R,S 103 FW1 SEQ ID NO: 94 EVHLVESGGGLVRPG sequence no. 3GSLRLSCAAFGFIFK P,R,S 103 FW1 SEQ ID NO: 95 QVQLAESGGGLVQPGsequence no. 4 GSLKLSCAASRTIVS P,R,S 103 FW1 SEQ ID NO: 96QEHLVESGGGLVDIG sequence no. 5 GSLRLSCAASERIFS P,R,S 103 FW1SEQ ID NO: 97 QVKLEESGGGLAQPG sequence no. 6 GSLRLSCVASGFTFSP,R,S 103 FW1 SEQ ID NO: 98 EVQLVESGGGLVQPG sequence no. 7GSLRLSCVCVSSGCT P,R,S 103 FW1 SEQ ID NO: 99 EVQLVESGGGLALPGsequence no. 8 GSLTLSCVFSGSTFSand in which

-   iv) FR2 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-20 Representative FW2 sequences forNanobodies of the P,R,S 103-group. P,R,S 103 FW2 SEQ ID NO: 102WFRQAPGKEREFVA sequence no. 1 P,R,S 103 FW2 SEQ ID NO: 103WVRQAPGKVLEWVS sequence no. 2 P,R,S 103 FW2 SEQ ID NO: 104WVRRPPGKGLEWVS sequence no. 3 P,R,S 103 FW2 SEQ ID NO: 105WIRQAPGKEREGVS sequence no. 4 P,R,S 103 FW2 SEQ ID NO: 106WVRQYPGKEPEWVS sequence no. 5 P,R,S 103 FW2 SEQ ID NO: 107WFRQPPGKEHEFVA sequence no. 6 P,R,S 103 FW2 SEQ ID NO: 108WYRQAPGKRTELVA sequence no. 7 P,R,S 103 FW2 SEQ ID NO: 109WLRQAPGQGLEWVS sequence no. 8 P,R,S 103 FW2 SEQ ID NO: 110WLRQTPGKGLEWVG sequence no. 9 P,R,S 103 FW2 SEQ ID NO: 111WVRQAPGKAEEFVS sequence no. 10and in which:

-   v) FR3 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-21 Representative FW3 sequences forNanobodies of the P,R,S 103-group. P,R,S 103 FW3 SEQ ID NO: 112RFTISRDNAKNTVYLQ sequence no. 1 MNSLKPEDTAVYYCAA P,R,S 103 FW3SEQ ID NO: 113 RFTISRDNARNTLYLQ sequence no. 2 MDSLIPEDTALYYCARP,R,S 103 FW3 SEQ ID NO: 114 RFTISRDNAKNEMYLQ sequence no. 3MNNLKTEDTGVYWCGA P,R,S 103 FW3 SEQ ID NO: 115 RFTISSDSNRNMIYLQsequence no. 4 MNNLKPEDTAVYYCAA P,R,S 103 FW3 SEQ ID NO: 116RFTISRDNAKNMLYLH sequence no. 5 LNNLKSEDTAVYYCRR P,R,S 103 FW3SEQ ID NO: 117 RFTISRDNAKKTVYLR sequence no. 6 LNSLNPEDTAVYSCNLP,R,S 103 FW3 SEQ ID NO: 118 RFKISRDNAKKTLYLQ sequence no. 7MNSLGPEDTAMYYCQR P,R,S 103 FW3 SEQ ID NO: 119 RFTVSRDNGKNTAYLRsequence no. 8 MNSLKPEDTADYYCAVand in which:

-   vi) FR4 is an amino acid sequence that has at least 80% amino acid    identity with at least one of the following amino acid sequences:

TABLE B-22 Representative FW4 sequences forNanobodies of the P,R,S 103-group. P,R,S 103 FW4 SEQ ID NO: 120RGQGTQVTVSS sequence no. 1 P,R,S 103 FW4 SEQ ID NO: 121 LRGGTQVTVSSsequence no. 2 P,R,S 103 FW4 SEQ ID NO: 122 GNKGTLVTVSS sequence no. 3P,R,S 103 FW4 SEQ ID NO: 123 SSPGTQVTVSS sequence no. 4 P,R,S 103 FW4SEQ ID NO: 124 SSQGTLVTVSS sequence no. 5 P,R,S 103 FW4 SEQ ID NO: 125RSRGIQVTVSS sequence no. 6and in which:

-   vii) CDR1, CDR2 and CDR3 are as defined herein, and are preferably    as defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

In the above Nanobodies, one or more of the further Hallmark residuesare preferably as described herein (for example, when they are V_(HH)sequences or partially humanized Nanobodies).

With regard to framework 1, it will again be clear to the skilled personthat, for determining the degree of amino acid identity, the amino acidresidues on positions 1 to 4 and 27 to 30 are preferably disregarded.

In view of this, a Nanobody of the P,R,S 103 class may be an amino acidsequence that is comprised of four framework regions/sequencesinterrupted by three complementarity determining regions/sequences, inwhich:

-   i) the amino acid residue at position 103 according to the Kabat    numbering is different from W;    and in which:-   ii) preferably the amino acid residue at position 103 according to    the Kabat numbering is P, R or S, and more preferably R;    and in which:-   iii) FR1 is an amino acid sequence that, on positions 5 to 26 of the    Kabat numbering, has at least 80% amino acid identity with at least    one of the following amino acid sequences:

TABLE B-23 Representative FW1 sequences(amino acid residues 5 to 26) for Nanobodies of the P,R,S 103-group.P,R,S 103 FW1 SEQ ID NO: 100 VESGGGLVQAG sequence no. 9 GSLRLSCAASGP,R,S 103 FW1 SEQ ID NO: 101 AESGGGLVQPG sequence no. 10 GSLKLSCAASRand in which:

-   iv) FR2, FR3 and FR4 are as mentioned herein for FR2, FR3 and FR4 of    Nanobodies of the P,R,S 103 class;    and in which:-   v) CDR1, CDR2 and CDR3 are as defined herein, and are preferably as    defined according to one of the preferred aspects herein, and are    more preferably as defined according to one of the more preferred    aspects herein.

The above Nanobodies may for example be V_(HH) sequences or may behumanized Nanobodies. When the above Nanobody sequences are V_(HH)sequences, they may be suitably humanized, as further described herein.When the Nanobodies are partially humanized Nanobodies, they mayoptionally be further suitably humanized, again as described herein.

In the above Nanobodies, one or more of the further Hallmark residuesare preferably as described herein (for example, when they are V_(HH)sequences or partially humanized Nanobodies).

In another preferred, but non-limiting aspect, the invention relates toa Nanobody as described above, in which the CDR sequences have at least70% amino acid identity, preferably at least 80% amino acid identity,more preferably at least 90% amino acid identity, such as 95% amino acididentity or more or even essentially 100% amino acid identity with theCDR sequences of at least one of the amino acid sequences of SEQ IDNO's: 179 to 185 (see Table A-1). This degree of amino acid identity canfor example be determined by determining the degree of amino acididentity (in a manner described herein) between said Nanobody and one ormore of the sequences of SEQ ID NO's: 179 to 185 (see Table A-1), inwhich the amino acid residues that form the framework regions aredisregarded. Such Nanobodies can be as further described herein.

As already mentioned herein, another preferred but non-limiting aspectof the invention relates to a Nanobody with an amino acid sequence thatis chosen from the group consisting of SEQ ID NO's: 179 to 185 (seeTable A-1) or from the group consisting of from amino acid sequencesthat have more than 80%, preferably more than 90%, more preferably morethan 95%, such as 99% or more sequence identity (as defined herein) withat least one of the amino acid sequences of SEQ ID NO's: 179 to 185 (seeTable A-1).

Also, in the above Nanobodies:

-   i) any amino acid substitution (when it is not a humanizing    substitution as defined herein) is preferably, and compared to the    corresponding amino acid sequence of SEQ ID NO's: 179 to 185 (see    Table A-1), a conservative amino acid substitution, (as defined    herein);    and/or:-   ii) its amino acid sequence preferably contains either only amino    acid substitutions, or otherwise preferably no more than 5,    preferably no more than 3, and more preferably only 1 or 2 amino    acid deletions or insertions, compared to the corresponding amino    acid sequence of SEQ ID NO's: 179 to 185 (see Table A-1);    and/or-   iii) the CDR's may be CDR's that are derived by means of affinity    maturation, for example starting from the CDR's of to the    corresponding amino acid sequence of SEQ ID NO's: 179 to 185 (see    Table A-1).

Preferably, the CDR sequences and FR sequences in the Nanobodies of theinvention are such that the Nanobodies of the invention (andpolypeptides of the invention comprising the same):

-   -   bind to OX40L with a dissociation constant (K_(D)) of 10⁻⁵ to        10⁻¹² moles/liter or less, and preferably 10⁻⁷ to 10⁻¹²        moles/liter or less and more preferably 10⁻⁸ to 10⁻¹²        moles/liter (i.e. with an association constant (K_(A)) of 10⁵ to        10¹² liter/moles or more, and preferably 10⁷ to 10¹² liter/moles        or more and more preferably 10⁸ to 10¹² liter/moles);        and/or such that they:    -   bind to OX40L with a k_(on)-rate of between 10² M⁻¹s⁻¹ to about        10⁷ M⁻¹s⁻¹, preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more        preferably between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between        10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹;        and/or such that they:    -   bind to OX40L with a k_(off) rate between 1 s⁻¹ (t_(1/2)=0.69 s)        and 10⁻⁶s⁻¹ (providing a near irreversible complex with a        t_(1/2) of multiple days), preferably between 10⁻²s⁻¹ and 10⁻⁶        s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as        between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.

Preferably, CDR sequences and FR sequences present in the Nanobodies ofthe invention are such that the Nanobodies of the invention will bind toOX40L with an affinity less than 500 nM, preferably less than 200 nM,more preferably less than 10 nM, such as less than 500 pM.

According to one non-limiting aspect of the invention, a Nanobody may beas defined herein, but with the proviso that it has at least “one aminoacid difference” (as defined herein) in at least one of the frameworkregions compared to the corresponding framework region of a naturallyoccurring human V_(H) domain, and in particular compared to thecorresponding framework region of DP-47. More specifically, according toone non-limiting aspect of the invention, a Nanobody may be as definedherein, but with the proviso that it has at least “one amino aciddifference” (as defined herein) at at least one of the Hallmark residues(including those at positions 108, 103 and/or 45) compared to thecorresponding framework region of a naturally occurring human V_(H)domain, and in particular compared to the corresponding framework regionof DP-47. Usually, a Nanobody will have at least one such amino aciddifference with a naturally occurring V_(H) domain in at least one ofFR2 and/or FR4, and in particular at at least one of the Hallmarkresidues in FR2 and/or FR4 (again, including those at positions 108, 103and/or 45).

Also, a humanized Nanobody of the invention may be as defined herein,but with the proviso that it has at least “one amino acid difference”(as defined herein) in at least one of the framework regions compared tothe corresponding framework region of a naturally occurring V_(HH)domain. More specifically, according to one non-limiting aspect of theinvention, a humanized Nanobody may be as defined herein, but with theproviso that it has at least “one amino acid difference” (as definedherein) at at least one of the Hallmark residues (including those atpositions 108, 103 and/or 45) compared to the corresponding frameworkregion of a naturally occurring V_(HH) domain. Usually, a humanizedNanobody will have at least one such amino acid difference with anaturally occurring V_(HH) domain in at least one of FR2 and/or FR4, andin particular at at least one of the Hallmark residues in FR2 and/or FR4(again, including those at positions 108, 103 and/or 45).

As will be clear from the disclosure herein, it is also within the scopeof the invention to use natural or synthetic analogs, mutants, variants,alleles, homologs and orthologs (herein collectively referred to as“analogs”) of the Nanobodies of the invention as defined herein, and inparticular analogs of the Nanobodies of SEQ ID NO's 179 to 185 (seeTable A-1). Thus, according to one aspect of the invention, the term“Nanobody of the invention” in its broadest sense also covers suchanalogs.

Generally, in such analogs, one or more amino acid residues may havebeen replaced, deleted and/or added, compared to the Nanobodies of theinvention as defined herein. Such substitutions, insertions or deletionsmay be made in one or more of the framework regions and/or in one ormore of the CDR's. When such substitutions, insertions or deletions aremade in one or more of the framework regions, they may be made at one ormore of the Hallmark residues and/or at one or more of the otherpositions in the framework residues, although substitutions, insertionsor deletions at the Hallmark residues are generally less preferred(unless these are suitable humanizing substitutions as describedherein).

By means of non-limiting examples, a substitution may for example be aconservative substitution (as described herein) and/or an amino acidresidue may be replaced by another amino acid residue that naturallyoccurs at the same position in another V_(HH) domain (see Tables B-4 toB-7 for some non-limiting examples of such substitutions), although theinvention is generally not limited thereto. Thus, any one or moresubstitutions, deletions or insertions, or any combination thereof, thateither improve the properties of the Nanobody of the invention or thatat least do not detract too much from the desired properties or from thebalance or combination of desired properties of the Nanobody of theinvention (i.e. to the extent that the Nanobody is no longer suited forits intended use) are included within the scope of the invention. Askilled person will generally be able to determine and select suitablesubstitutions, deletions or insertions, or suitable combinations ofthereof, based on the disclosure herein and optionally after a limiteddegree of routine experimentation, which may for example involveintroducing a limited number of possible substitutions and determiningtheir influence on the properties of the Nanobodies thus obtained.

For example, and depending on the host organism used to express theNanobody or polypeptide of the invention, such deletions and/orsubstitutions may be designed in such a way that one or more sites forpost-translational modification (such as one or more glycosylationsites) are removed, as will be within the ability of the person skilledin the art. Alternatively, substitutions or insertions may be designedso as to introduce one or more sites for attachment of functional groups(as described herein), for example to allow site-specific pegylation(again as described herein).

As can be seen from the data on the V_(HH) entropy and V_(HH)variability given in Tables B-4 to B-7 above, some amino acid residuesin the framework regions are more conserved than others. Generally,although the invention in its broadest sense is not limited thereto, anysubstitutions, deletions or insertions are preferably made at positionsthat are less conserved. Also, generally, amino acid substitutions arepreferred over amino acid deletions or insertions.

The analogs are preferably such that they can bind to OX40L with anaffinity (suitably measured and/or expressed as a K_(D)-value (actual orapparent), a K_(A)-value (actual or apparent), a k_(on)-rate and/or ak_(off)-rate, or alternatively as an IC₅₀ value, as further describedherein) that is as defined herein for the Nanobodies of the invention.

The analogs are preferably also such that they retain the favourableproperties the Nanobodies, as described herein.

Also, according to one preferred aspect, the analogs have a degree ofsequence identity of at least 70%, preferably at least 80%, morepreferably at least 90%, such as at least 95% or 99% or more; and/orpreferably have at most 20, preferably at most 10, even more preferablyat most 5, such as 4, 3, 2 or only 1 amino acid difference (as definedherein), with one of the Nanobodies of SEQ ID NOs: 179 to 185 (see TableA-1).

Also, the framework sequences and CDR's of the analogs are preferablysuch that they are in accordance with the preferred aspects definedherein. More generally, as described herein, the analogs will have (a) aQ at position 108; and/or (b) a charged amino acid or a cysteine residueat position 45 and preferably an E at position 44, and more preferably Eat position 44 and R at position 45; and/or (c) P, R or S at position103.

One preferred class of analogs of the Nanobodies of the inventioncomprise Nanobodies that have been humanized (i.e. compared to thesequence of a naturally occurring Nanobody of the invention). Asmentioned in the background art cited herein, such humanizationgenerally involves replacing one or more amino acid residues in thesequence of a naturally occurring V_(HH) with the amino acid residuesthat occur at the same position in a human V_(H) domain, such as a humanV_(H)3 domain. Examples of possible humanizing substitutions orcombinations of humanizing substitutions will be clear to the skilledperson, for example from the Tables herein, from the possible humanizingsubstitutions mentioned in the background art cited herein, and/or froma comparison between the sequence of a Nanobody and the sequence of anaturally occurring human V_(H) domain.

The humanizing substitutions should be chosen such that the resultinghumanized Nanobodies still retain the favourable properties ofNanobodies as defined herein, and more preferably such that they are asdescribed for analogs in the preceding paragraphs. A skilled person willgenerally be able to determine and select suitable humanizingsubstitutions or suitable combinations of humanizing substitutions,based on the disclosure herein and optionally after a limited degree ofroutine experimentation, which may for example involve introducing alimited number of possible humanizing substitutions and determiningtheir influence on the properties of the Nanobodies thus obtained.

Generally, as a result of humanization, the Nanobodies of the inventionmay become more “human-like”, while still retaining the favorableproperties of the Nanobodies of the invention as described herein. As aresult, such humanized Nanobodies may have several advantages, such as areduced immunogenicity, compared to the corresponding naturallyoccurring V_(HH) domains. Again, based on the disclosure herein andoptionally after a limited degree of routine experimentation, theskilled person will be able to select humanizing substitutions orsuitable combinations of humanizing substitutions which optimize orachieve a desired or suitable balance between the favourable propertiesprovided by the humanizing substitutions on the one hand and thefavourable properties of naturally occurring V_(HH) domains on the otherhand.

The Nanobodies of the invention may be suitably humanized at anyframework residue(s), such as at one or more Hallmark residues (asdefined herein) or at one or more other framework residues (i.e.non-Hallmark residues) or any suitable combination thereof. Onepreferred humanizing substitution for Nanobodies of the “P,R,S-103group” or the “KERE group” is Q108 into L108. Nanobodies of the “GLEWclass” may also be humanized by a Q108 into L108 substitution, providedat least one of the other Hallmark residues contains a camelid(camelizing) substitution (as defined herein). For example, as mentionedabove, one particularly preferred class of humanized Nanobodies has GLEWor a GLEW-like sequence at positions 44-47; P, R or S (and in particularR) at position 103, and an L at position 108.

The humanized and other analogs, and nucleic acid sequences encoding thesame, can be provided in any manner known per se, for example using oneor more of the techniques mentioned on pages 103 and 104 of WO08/020079.

Also, in addition to humanizing substitutions as described herein, theamino acid sequences of the invention may contain one or moreother/further substitutions. Again, some preferred, but non-limitingexamples of such other/further substitutions will become clear from thefurther description herein, and for example may include (and preferablyessentially consist of) one or more of the following substitutions:

-   -   (a) one or more conservative amino acid substitutions; and/or    -   (b) one or more substitutions in which a “camelid” amino acid        residue at a certain position is replaced by a different        “camelid” amino acid residue that occurs at said position, for        which reference is for example made to Tables A-6 to A-9 from        PCT/EP2008/066365 (published on Jun. 4, 2009 as WO 09/068627),        which mention the various Camelid residues that occur as each        amino acid position in wild-type VHH's. Such substitutions may        even comprise suitable substitutions of an amino acid residue        that occurs at a Hallmark position with another amino acid        residue that occurding at a Hallmark position in a wild-type VHH        (for which reference is for example made to Tables A-6 to A-9        from PCT/EP2008/066365); and/or    -   (c) one or more substitutions that improve the (other)        properties of the protein, such as substitutions that improve        the long-term stability and/or properties under storage of the        protein. These may for example and without limitation be        substitutions that prevent or reduce oxidation events (for        example, of methionine residues); that prevent or reduce        pyroglutamate formation; and/or that prevent or reduce        isomerisation or deamidation of aspartic acids or asparagines        (for example, of DG, DS, NG or NS motifs). For such        substitutions, reference is for example made to the        International application WO 09/095235, which is generally        directed to methods for stabilizing single immunoglobulin        variable domains by means of such substitutions, and also gives        some specific example of suitable substitutions (see for example        pages 4 and 5 and pages 10 to 15). One example of such        substitution may be to replace an NS motif at positions 82a and        82b with an NN motif.

As mentioned there, it will be also be clear to the skilled person thatthe Nanobodies of the invention (including their analogs) can bedesigned and/or prepared starting from human V_(H) sequences (i.e. aminoacid sequences or the corresponding nucleotide sequences), such as forexample from human V_(H)3 sequences such as DP-47, DP-51 or DP-29, i.e.by introducing one or more camelizing substitutions (i.e. changing oneor more amino acid residues in the amino acid sequence of said humanV_(H) domain into the amino acid residues that occur at thecorresponding position in a V_(HH) domain), so as to provide thesequence of a Nanobody of the invention and/or so as to confer thefavourable properties of a Nanobody to the sequence thus obtained.Again, this can generally be performed using the various methods andtechniques referred to in the previous paragraph, using an amino acidsequence and/or nucleotide sequence for a human V_(H) domain as astarting point.

Some preferred, but non-limiting camelizing substitutions can be derivedfrom Tables B-4-B-7. It will also be clear that camelizing substitutionsat one or more of the Hallmark residues will generally have a greaterinfluence on the desired properties than substitutions at one or more ofthe other amino acid positions, although both and any suitablecombination thereof are included within the scope of the invention. Forexample, it is possible to introduce one or more camelizingsubstitutions that already confer at least some the desired properties,and then to introduce further camelizing substitutions that eitherfurther improve said properties and/or confer additional favourableproperties. Again, the skilled person will generally be able todetermine and select suitable camelizing substitutions or suitablecombinations of camelizing substitutions, based on the disclosure hereinand optionally after a limited degree of routine experimentation, whichmay for example involve introducing a limited number of possiblecamelizing substitutions and determining whether the favourableproperties of Nanobodies are obtained or improved (i.e. compared to theoriginal V_(H) domain).

Generally, however, such camelizing substitutions are preferably suchthat the resulting an amino acid sequence at least contains (a) a Q atposition 108; and/or (b) a charged amino acid or a cysteine residue atposition 45 and preferably also an E at position 44, and more preferablyE at position 44 and R at position 45; and/or (c) P, R or S at position103; and optionally one or more further camelizing substitutions. Morepreferably, the camelizing substitutions are such that they result in aNanobody of the invention and/or in an analog thereof (as definedherein), such as in a humanized analog and/or preferably in an analogthat is as defined in the preceding paragraphs.

Nanobodies can also be derived from V_(H) domains by the incorporationof substitutions that are rare in nature, but nonetheless, structurallycompatible with the VH domain fold. For example, but without beinglimiting, these substitutions may include on or more of the following:Gly at position 35, Ser, Val or Thr at position 37, Ser, Thr, Arg, Lys,His, Asp or Glu at position 39, Glu or His at position 45, Trp, Leu,Val, Ala, Thr, or Glu at position 47, S or R at position 50. (Barthelemyet al. J Biol Chem. 2008 Feb. 8; 283(6):3639-54. Epub 2007 Nov. 28)

As will also be clear from the disclosure herein, it is also within thescope of the invention to use parts or fragments, or combinations of twoor more parts or fragments, of the Nanobodies of the invention asdefined herein, and in particular parts or fragments of the Nanobodiesof SEQ ID NO's: 179 to 185 (see Table A-1). Thus, according to oneaspect of the invention, the term “Nanobody of the invention” in itsbroadest sense also covers such parts or fragments.

Generally, such parts or fragments of the Nanobodies of the invention(including analogs thereof) have amino acid sequences in which, comparedto the amino acid sequence of the corresponding full length Nanobody ofthe invention (or analog thereof), one or more of the amino acidresidues at the N-terminal end, one or more amino acid residues at theC-terminal end, one or more contiguous internal amino acid residues, orany combination thereof, have been deleted and/or removed.

The parts or fragments are preferably such that they can bind to OX40Lwith an affinity (suitably measured and/or expressed as a K_(D)-value(actual or apparent), a K_(A)-value (actual or apparent), a k_(on)-rateand/or a k_(off)-rate, or alternatively as an IC₅₀ value, as furtherdescribed herein) that is as defined herein for the Nanobodies of theinvention.

Any part or fragment is preferably such that it comprises at least 10contiguous amino acid residues, preferably at least 20 contiguous aminoacid residues, more preferably at least 30 contiguous amino acidresidues, such as at least 40 contiguous amino acid residues, of theamino acid sequence of the corresponding full length Nanobody of theinvention.

Also, any part or fragment is such preferably that it comprises at leastone of CDR1, CDR2 and/or CDR3 or at least part thereof (and inparticular at least CDR3 or at least part thereof). More preferably, anypart or fragment is such that it comprises at least one of the CDR's(and preferably at least CDR3 or part thereof) and at least one otherCDR (i.e. CDR1 or CDR2) or at least part thereof, preferably connectedby suitable framework sequence(s) or at least part thereof. Morepreferably, any part or fragment is such that it comprises at least oneof the CDR's (and preferably at least CDR3 or part thereof) and at leastpart of the two remaining CDR's, again preferably connected by suitableframework sequence(s) or at least part thereof.

According to another particularly preferred, but non-limiting aspect,such a part or fragment comprises at least CDR3, such as FR3, CDR3 andFR4 of the corresponding full length Nanobody of the invention, i.e. asfor example described in the International application WO 03/050531(Lasters et al.).

As already mentioned above, it is also possible to combine two or moreof such parts or fragments (i.e. from the same or different Nanobodiesof the invention), i.e. to provide an analog (as defined herein) and/orto provide further parts or fragments (as defined herein) of a Nanobodyof the invention. It is for example also possible to combine one or moreparts or fragments of a Nanobody of the invention with one or more partsor fragments of a human V_(H) domain.

According to one preferred aspect, the parts or fragments have a degreeof sequence identity of at least 50%, preferably at least 60%, morepreferably at least 70%, even more preferably at least 80%, such as atleast 90%, 95% or 99% or more with one of the Nanobodies of SEQ ID NOs179 to 185 (see Table A-1).

The parts and fragments, and nucleic acid sequences encoding the same,can be provided and optionally combined in any manner known per se. Forexample, such parts or fragments can be obtained by inserting a stopcodon in a nucleic acid that encodes a full-sized Nanobody of theinvention, and then expressing the nucleic acid thus obtained in amanner known per se (e.g. as described herein). Alternatively, nucleicacids encoding such parts or fragments can be obtained by suitablyrestricting a nucleic acid that encodes a full-sized Nanobody of theinvention or by synthesizing such a nucleic acid in a manner known perse. Parts or fragments may also be provided using techniques for peptidesynthesis known per se.

The invention in its broadest sense also comprises derivatives of theNanobodies of the invention. Such derivatives can generally be obtainedby modification, and in particular by chemical and/or biological (e.g.enzymatical) modification, of the Nanobodies of the invention and/or ofone or more of the amino acid residues that form the Nanobodies of theinvention.

Examples of such modifications, as well as examples of amino acidresidues within the Nanobody sequence that can be modified in such amanner (i.e. either on the protein backbone but preferably on a sidechain), methods and techniques that can be used to introduce suchmodifications and the potential uses and advantages of suchmodifications will be clear to the skilled person.

For example, such a modification may involve the introduction (e.g. bycovalent linking or in an other suitable manner) of one or morefunctional groups, residues or moieties into or onto the Nanobody of theinvention, and in particular of one or more functional groups, residuesor moieties that confer one or more desired properties orfunctionalities to the Nanobody of the invention. Example of suchfunctional groups will be clear to the skilled person.

For example, such modification may comprise the introduction (e.g. bycovalent binding or in any other suitable manner) of one or morefunctional groups that increase the half-life, the solubility and/or theabsorption of the Nanobody of the invention, that reduce theimmunogenicity and/or the toxicity of the Nanobody of the invention,that eliminate or attenuate any undesirable side effects of the Nanobodyof the invention, and/or that confer other advantageous properties toand/or reduce the undesired properties of the Nanobodies and/orpolypeptides of the invention; or any combination of two or more of theforegoing. Examples of such functional groups and of techniques forintroducing them will be clear to the skilled person, and can generallycomprise all functional groups and techniques mentioned in the generalbackground art cited hereinabove as well as the functional groups andtechniques known per se for the modification of pharmaceutical proteins,and in particular for the modification of antibodies or antibodyfragments (including ScFv's and single domain antibodies), for whichreference is for example made to Remington's Pharmaceutical Sciences,16th ed., Mack Publishing Co., Easton, Pa. (1980). Such functionalgroups may for example be linked directly (for example covalently) to aNanobody of the invention, or optionally via a suitable linker orspacer, as will again be clear to the skilled person.

One of the most widely used techniques for increasing the half-lifeand/or reducing the immunogenicity of pharmaceutical proteins comprisesattachment of a suitable pharmacologically acceptable polymer, such aspoly(ethyleneglycol) (PEG) or derivatives thereof (such asmethoxypoly(ethyleneglycol) or mPEG). Generally, any suitable form ofpegylation can be used, such as the pegylation used in the art forantibodies and antibody fragments (including but not limited to (single)domain antibodies and ScFv's); reference is made to for example Chapman,Nat. Biotechnol., 54, 531-545 (2002); by Veronese and Harris, Adv. DrugDeliv. Rev. 54, 453-456 (2003), by Harris and Chess, Nat. Rev. Drug.Discov., 2, (2003) and in WO 04/060965. Various reagents for pegylationof proteins are also commercially available, for example from NektarTherapeutics, USA.

Preferably, site-directed pegylation is used, in particular via acysteine-residue (see for example Yang et al., Protein Engineering, 16,10, 761-770 (2003). For example, for this purpose, PEG may be attachedto a cysteine residue that naturally occurs in a Nanobody of theinvention, a Nanobody of the invention may be modified so as to suitablyintroduce one or more cysteine residues for attachment of PEG, or anamino acid sequence comprising one or more cysteine residues forattachment of PEG may be fused to the N- and/or C-terminus of a Nanobodyof the invention, all using techniques of protein engineering known perse to the skilled person.

Preferably, for the Nanobodies and proteins of the invention, a PEG isused with a molecular weight of more than 5000, such as more than 10,000and less than 200,000, such as less than 100,000; for example in therange of 20,000-80,000.

Another, usually less preferred modification comprises N-linked orO-linked glycosylation, usually as part of co-translational and/orpost-translational modification, depending on the host cell used forexpressing the Nanobody or polypeptide of the invention.

Yet another modification may comprise the introduction of one or moredetectable labels or other signal-generating groups or moieties,depending on the intended use of the labelled Nanobody. Suitable labelsand techniques for attaching, using and detecting them will be clear tothe skilled person, and for example include, but are not limited to, thefluorescent labels, phosphorescent labels, chemiluminescent labels,bioluminescent labels, radio-isotopes, metals, metal chelates, metalliccations, chromophores and enzymes, such as those mentioned on page 109of WO 08/020079. Other suitable labels will be clear to the skilledperson, and for example include moieties that can be detected using NMRor ESR spectroscopy.

Such labelled Nanobodies and polypeptides of the invention may forexample be used for in vitro, in vivo or in situ assays (includingimmunoassays known per se such as ELISA, RIA, EIA and other “sandwichassays”, etc.) as well as in vivo diagnostic and imaging purposes,depending on the choice of the specific label.

As will be clear to the skilled person, another modification may involvethe introduction of a chelating group, for example to chelate one of themetals or metallic cations referred to above. Suitable chelating groupsfor example include, without limitation, diethyl-enetriaminepentaaceticacid (DTPA) or ethylenediaminetetraacetic acid (EDTA).

Yet another modification may comprise the introduction of a functionalgroup that is one part of a specific binding pair, such as thebiotin-(strept)avidin binding pair. Such a functional group may be usedto link the Nanobody of the invention to another protein, polypeptide orchemical compound that is bound to the other half of the binding pair,i.e. through formation of the binding pair. For example, a Nanobody ofthe invention may be conjugated to biotin, and linked to anotherprotein, polypeptide, compound or carrier conjugated to avidin orstreptavidin. For example, such a conjugated Nanobody may be used as areporter, for example in a diagnostic system where a detectablesignal-producing agent is conjugated to avidin or streptavidin. Suchbinding pairs may for example also be used to bind the Nanobody of theinvention to a carrier, including carriers suitable for pharmaceuticalpurposes. One non-limiting example are the liposomal formulationsdescribed by Cao and Suresh, Journal of Drug Targetting, 8, 4, 257(2000). Such binding pairs may also be used to link a therapeuticallyactive agent to the Nanobody of the invention.

For some applications, in particular for those applications in which itis intended to kill a cell that expresses the target against which theNanobodies of the invention are directed (e.g. in the treatment ofcancer), or to reduce or slow the growth and/or proliferation such acell, the Nanobodies of the invention may also be linked to a toxin orto a toxic residue or moiety. Examples of toxic moieties, compounds orresidues which can be linked to a Nanobody of the invention toprovide—for example—a cytotoxic compound will be clear to the skilledperson and can for example be found in the prior art cited above and/orin the further description herein. One example is the so-called ADEPT″technology described in WO 03/055527.

Other potential chemical and enzymatical modifications will be clear tothe skilled person. Such modifications may also be introduced forresearch purposes (e.g. to study function-activity relationships).Reference is for example made to Lundblad and Bradshaw, Biotechnol.Appl. Biochem., 26, 143-151 (1997).

Preferably, the derivatives are such that they bind to OX40L with anaffinity (suitably measured and/or expressed as a K_(D)-value (actual orapparent), a K_(A)-value (actual or apparent), a k_(on)-rate and/or ak_(off)-rate, or alternatively as an IC₅₀ value, as further describedherein) that is as defined herein for the Nanobodies of the invention.

As mentioned above, the invention also relates to proteins orpolypeptides that essentially consist of or comprise at least oneNanobody of the invention. By “essentially consist of” is meant that theamino acid sequence of the polypeptide of the invention either isexactly the same as the amino acid sequence of a Nanobody of theinvention or corresponds to the amino acid sequence of a Nanobody of theinvention which has a limited number of amino acid residues, such as1-20 amino acid residues, for example 1-10 amino acid residues andpreferably 1-6 amino acid residues, such as 1, 2, 3, 4, 5 or 6 aminoacid residues, added at the amino terminal end, at the carboxy terminalend, or at both the amino terminal end and the carboxy terminal end ofthe amino acid sequence of the Nanobody.

Said amino acid residues may or may not change, alter or otherwiseinfluence the (biological) properties of the Nanobody and may or may notadd further functionality to the Nanobody. For example, such amino acidresidues:

-   -   can comprise an N-terminal Met residue, for example as result of        expression in a heterologous host cell or host organism.    -   may form a signal sequence or leader sequence that directs        secretion of the Nanobody from a host cell upon synthesis.        Suitable secretory leader peptides will be clear to the skilled        person, and may be as further described herein. Usually, such a        leader sequence will be linked to the N-terminus of the        Nanobody, although the invention in its broadest sense is not        limited thereto;    -   may form a sequence or signal that allows the Nanobody to be        directed towards and/or to penetrate or enter into specific        organs, tissues, cells, or parts or compartments of cells,        and/or that allows the Nanobody to penetrate or cross a        biological barrier such as a cell membrane, a cell layer such as        a layer of epithelial cells, a tumor including solid tumors, or        the blood-brain-barrier. Examples of such amino acid sequences        will be clear to the skilled person and include those mentioned        in paragraph c) on page 112 of WO 08/020079.    -   may form a “tag”, for example an amino acid sequence or residue        that allows or facilitates the purification of the Nanobody, for        example using affinity techniques directed against said sequence        or residue. Thereafter, said sequence or residue may be removed        (e.g. by chemical or enzymatical cleavage) to provide the        Nanobody sequence (for this purpose, the tag may optionally be        linked to the Nanobody sequence via a cleavable linker sequence        or contain a cleavable motif). Some preferred, but non-limiting        examples of such residues are multiple histidine residues,        glutathione residues and a myc-tag (see for example SEQ ID NO:31        of WO 06/12282).    -   may be one or more amino acid residues that have been        functionalized and/or that can serve as a site for attachment of        functional groups. Suitable amino acid residues and functional        groups will be clear to the skilled person and include, but are        not limited to, the amino acid residues and functional groups        mentioned herein for the derivatives of the Nanobodies of the        invention.

According to another aspect, a polypeptide of the invention comprises aNanobody of the invention, which is fused at its amino terminal end, atits carboxy terminal end, or both at its amino terminal end and at itscarboxy terminal end to at least one further amino acid sequence, i.e.so as to provide a fusion protein comprising said Nanobody of theinvention and the one or more further amino acid sequences. Such afusion will also be referred to herein as a “Nanobody fusion”.

The one or more further amino acid sequence may be any suitable and/ordesired amino acid sequences. The further amino acid sequences may ormay not change, alter or otherwise influence the (biological) propertiesof the Nanobody, and may or may not add further functionality to theNanobody or the polypeptide of the invention. Preferably, the furtheramino acid sequence is such that it confers one or more desiredproperties or functionalities to the Nanobody or the polypeptide of theinvention.

For example, the further amino acid sequence may also provide a secondbinding site, which binding site may be directed against any desiredprotein, polypeptide, antigen, antigenic determinant or epitope(including but not limited to the same protein, polypeptide, antigen,antigenic determinant or epitope against which the Nanobody of theinvention is directed, or a different protein, polypeptide, antigen,antigenic determinant or epitope).

Example of such amino acid sequences will be clear to the skilledperson, and may generally comprise all amino acid sequences that areused in peptide fusions based on conventional antibodies and fragmentsthereof (including but not limited to ScFv's and single domainantibodies). Reference is for example made to the review by Holliger andHudson, Nature Biotechnology, 23, 9, 1126-1136 (2005).

For example, such an amino acid sequence may be an amino acid sequencethat increases the half-life, the solubility, or the absorption, reducesthe immunogenicity or the toxicity, eliminates or attenuates undesirableside effects, and/or confers other advantageous properties to and/orreduces the undesired properties of the polypeptides of the invention,compared to the Nanobody of the invention per se. Some non-limitingexamples of such amino acid sequences are serum proteins, such as humanserum albumin (see for example WO 00/27435) or haptenic molecules (forexample haptens that are recognized by circulating antibodies, see forexample WO 98/22141).

In particular, it has been described in the art that linking fragmentsof immunoglobulins (such as V_(H) domains) to serum albumin or tofragments thereof can be used to increase the half-life. Reference isfor made to WO 00/27435 and WO 01/077137). According to the invention,the Nanobody of the invention is preferably either directly linked toserum albumin (or to a suitable fragment thereof) or via a suitablelinker, and in particular via a suitable peptide linked so that thepolypeptide of the invention can be expressed as a genetic fusion(protein). According to one specific aspect, the Nanobody of theinvention may be linked to a fragment of serum albumin that at leastcomprises the domain Ill of serum albumin or part thereof. Reference isfor example made to WO 07/112940 of Ablynx N.V.

Alternatively, the further amino acid sequence may provide a secondbinding site or binding unit that is directed against a serum protein(such as, for example, human serum albumin or another serum protein suchas IgG), so as to provide increased half-life in serum. Such amino acidsequences for example include the Nanobodies described below, as well asthe small peptides and binding proteins described in WO 91/01743, WO01/45746 and WO 02/076489 and the dAb's described in WO 03/002609 and WO04/003019. Reference is also made to Harmsen et al., Vaccine, 23 (41);4926-42, 2005, as well as to EP 0 368 684, as well as to WO 08/028977,WO 08/043821, WO 08/043822 by Ablynx N.V. and US provisional applicationof Ablynx N.V. entitled “Peptides capable of binding to serum proteins”filed on Dec. 5, 2006 ((see also PCT/EP2007/063348).

Such amino acid sequences may in particular be directed against serumalbumin (and more in particular human serum albumin) and/or against IgG(and more in particular human IgG). For example, such amino acidsequences may be amino acid sequences that are directed against (human)serum albumin and amino acid sequences that can bind to amino acidresidues on (human) serum albumin that are not involved in binding ofserum albumin to FcRn (see for example WO 06/0122787) and/or amino acidsequences that are capable of binding to amino acid residues on serumalbumin that do not form part of domain Ill of serum albumin (see againfor example WO 06/0122787); amino acid sequences that have or canprovide an increased half-life (see for example WO 08/028977 by AblynxN.V.); amino acid sequences against human serum albumin that arecross-reactive with serum albumin from at least one species of mammal,and in particular with at least one species of primate (such as, withoutlimitation, monkeys from the genus Macaca (such as, and in particular,cynomolgus monkeys (Macaca fascicularis) and/or rhesus monkeys (Macacamulatta)) and baboon (Papio ursinus), reference is again made to WO08/028977; amino acid sequences that can bind to serum albumin in a pHindependent manner (see for example WO 08/043821 by Ablynx N.V. entitled“Amino acid sequences that bind to serum proteins in a manner that isessentially independent of the pH, compounds comprising the same, anduses thereof”) and/or amino acid sequences that are conditional binders(see for example WO 08/043822 by Ablynx N.V. entitled “Amino acidsequences that bind to a desired molecule in a conditional manner”).

According to another aspect, the one or more further amino acidsequences may comprise one or more parts, fragments or domains ofconventional 4-chain antibodies (and in particular human antibodies)and/or of heavy chain antibodies. For example, although usually lesspreferred, a Nanobody of the invention may be linked to a conventional(preferably human) V_(H) or V_(L) domain or to a natural or syntheticanalog of a V_(H) or V_(L) domain, again optionally via a linkersequence (including but not limited to other (single) domain antibodies,such as the dAb's described by Ward et al.).

The at least one Nanobody may also be linked to one or more (preferablyhuman) C_(H)1, C_(H)2 and/or C_(H)3 domains, optionally via a linkersequence. For instance, a Nanobody linked to a suitable C_(H)1 domaincould for example be used—together with suitable light chains—togenerate antibody fragments/structures analogous to conventional Fabfragments or F(ab′)₂ fragments, but in which one or (in case of anF(ab′)₂ fragment) one or both of the conventional V_(H) domains havebeen replaced by a Nanobody of the invention. Also, two Nanobodies couldbe linked to a C_(H)3 domain (optionally via a linker) to provide aconstruct with increased half-life in vivo.

According to one specific aspect of a polypeptide of the invention, oneor more Nanobodies of the invention may be linked (optionally via asuitable linker or hinge region) to one or more constant domains (forexample, 2 or 3 constant domains that can be used as part of/to form anFc portion), to an Fc portion and/or to one or more antibody parts,fragments or domains that confer one or more effector functions to thepolypeptide of the invention and/or may confer the ability to bind toone or more Fc receptors. For example, for this purpose, and withoutbeing limited thereto, the one or more further amino acid sequences maycomprise one or more C_(H)2 and/or C_(H)3 domains of an antibody, suchas from a heavy chain antibody (as described herein) and more preferablyfrom a conventional human 4-chain antibody; and/or may form (part of)and Fc region, for example from IgG (e.g. from IgG1, IgG2, IgG3 orIgG4), from IgE or from another human Ig such as IgA, IgD or IgM. Forexample, WO 94/04678 describes heavy chain antibodies comprising aCamelid V_(HH) domain or a humanized derivative thereof (i.e. aNanobody), in which the Camelidae C_(H)2 and/or C_(H)3 domain have beenreplaced by human C_(H)2 and C_(H)3 domains, so as to provide animmunoglobulin that consists of 2 heavy chains each comprising aNanobody and human C_(H)2 and C_(H)3 domains (but no C_(H)1 domain),which immunoglobulin has the effector function provided by the C_(H)2and C_(H)3 domains and which immunoglobulin can function without thepresence of any light chains. Other amino acid sequences that can besuitably linked to the Nanobodies of the invention so as to provide aneffector function will be clear to the skilled person, and may be chosenon the basis of the desired effector function(s). Reference is forexample made to WO 04/058820, WO 99/42077, WO 02/056910 and WO05/017148, as well as the review by Holliger and Hudson, supra; and tothe non-prepublished US provisional application by Ablynx N.V. entitled“Constructs comprising single variable domains and an Fc portion derivedfrom IgE” which has a filing date of Dec. 4, 2007. Coupling of aNanobody of the invention to an Fc portion may also lead to an increasedhalf-life, compared to the corresponding Nanobody of the invention. Forsome applications, the use of an Fc portion and/or of constant domains(i.e. C_(H)2 and/or C_(H)3 domains) that confer increased half-lifewithout any biologically significant effector function may also besuitable or even preferred. Other suitable constructs comprising one ormore Nanobodies and one or more constant domains with increasedhalf-life in vivo will be clear to the skilled person, and may forexample comprise two Nanobodies linked to a C_(H)3 domain, optionallyvia a linker sequence. Generally, any fusion protein or derivatives withincreased half-life will preferably have a molecular weight of more than50 kD, the cut-off value for renal absorption.

In another one specific, but non-limiting, aspect, in order to form apolypeptide of the invention, one or more amino acid sequences of theinvention may be linked (optionally via a suitable linker or hingeregion) to naturally occurring, synthetic or semisynthetic constantdomains (or analogs, variants, mutants, parts or fragments thereof) thathave a reduced (or essentially no) tendency to self-associate intodimers (i.e. compared to constant domains that naturally occur inconventional 4-chain antibodies). Such monomeric (i.e. notself-associating) Fc chain variants, or fragments thereof, will be clearto the skilled person. For example, Helm et al., J Biol Chem 1996 2717494, describe monomeric Fc chain variants that can be used in thepolypeptide chains of the invention.

Also, such monomeric Fc chain variants are preferably such that they arestill capable of binding to the complement or the relevant Fcreceptor(s) (depending on the Fc portion from which they are derived),and/or such that they still have some or all of the effector functionsof the Fc portion from which they are derived (or at a reduced levelstill suitable for the intended use). Alternatively, in such apolypeptide chain of the invention, the monomeric Fc chain may be usedto confer increased half-life upon the polypeptide chain, in which casethe monomeric Fc chain may also have no or essentially no effectorfunctions.

Bivalent/multivalent, bispecific/multispecific orbiparatopic/multiparatopic polypeptides of the invention may also belinked to Fc portions, in order to provide polypeptide constructs of thetype that is described in the non-prepublished US provisionalapplication U.S. 61/005,331 entitled “immunoglobulin constructs” filedon Dec. 4, 2007.

The further amino acid sequences may also form a signal sequence orleader sequence that directs secretion of the Nanobody or thepolypeptide of the invention from a host cell upon synthesis (forexample to provide a pre-, pro- or prepro-form of the polypeptide of theinvention, depending on the host cell used to express the polypeptide ofthe invention).

The further amino acid sequence may also form a sequence or signal thatallows the Nanobody or polypeptide of the invention to be directedtowards and/or to penetrate or enter into specific organs, tissues,cells, or parts or compartments of cells, and/or that allows theNanobody or polypeptide of the invention to penetrate or cross abiological barrier such as a cell membrane, a cell layer such as a layerof epithelial cells, a tumor including solid tumors, or theblood-brain-barrier. Suitable examples of such amino acid sequences willbe clear to the skilled person, and for example include, but are notlimited to, those mentioned on page 118 of WO 08/020079. For someapplications, in particular for those applications in which it isintended to kill a cell that expresses the target against which theNanobodies of the invention are directed (e.g. in the treatment ofcancer), or to reduce or slow the growth and/or proliferation of such acell, the Nanobodies of the invention may also be linked to a(cyto)toxic protein or polypeptide. Examples of such toxic proteins andpolypeptides which can be linked to a Nanobody of the invention toprovide—for example—a cytotoxic polypeptide of the invention will beclear to the skilled person and can for example be found in the priorart cited above and/or in the further description herein. One example isthe so-called ADEPT″ technology described in WO 03/055527.

According to one preferred, but non-limiting aspect, said one or morefurther amino acid sequences comprise at least one further Nanobody, soas to provide a polypeptide of the invention that comprises at leasttwo, such as three, four, five or more Nanobodies, in which saidNanobodies may optionally be linked via one or more linker sequences (asdefined herein). As described on pages 119 and 120 of WO 08/020079,polypeptides of the invention that comprise two or more Nanobodies, ofwhich at least one is a Nanobody of the invention, will also be referredto herein as “multivalent” polypeptides of the invention, and theNanobodies present in such polypeptides will also be referred to hereinas being in a “multivalent format”. For example, “bivalent” and“trivalent” polypeptides of the invention may be as further described onpages 119 and 120 of WO 08/020079.

Polypeptides of the invention that contain at least two Nanobodies, inwhich at least one Nanobody is directed against a first antigen (i.e.against OX40L), and at least one Nanobody is directed against a secondantigen (i.e. different from OX40L), will also be referred to as“multispecific” polypeptides of the invention, and the Nanobodiespresent in such polypeptides will also be referred to herein as being ina “multispecific format”. Thus, for example, a “bispecific” polypeptideof the invention is a polypeptide that comprises at least one Nanobodydirected against a first antigen (i.e. OX40L), and at least one furtherNanobody directed against a second antigen (i.e. different from OX40L),whereas a “trispecific” polypeptide of the invention is a polypeptidethat comprises at least one Nanobody directed against a first antigen(i.e. OX40L), at least one further Nanobody directed against a secondantigen (i.e. different from OX40L), and at least one further Nanobodydirected against a third antigen (i.e. different from both OX40L, andthe second antigen); etc.

Accordingly, in its simplest form, a bispecific polypeptide of theinvention is a bivalent polypeptide of the invention (as definedherein), comprising a first Nanobody directed against OX40L, and asecond Nanobody directed against a second antigen, in which said firstand second Nanobody may optionally be linked via a linker sequence (asdefined herein); whereas a trispecific polypeptide of the invention inits simplest form is a trivalent polypeptide of the invention (asdefined herein), comprising a first Nanobody directed against OX40L, asecond Nanobody directed against a second antigen and a third Nanobodydirected against a third antigen, in which said first, second and thirdNanobody may optionally be linked via one or more, and in particular oneand more, in particular two, linker sequences.

However, as will be clear from the description hereinabove, theinvention is not limited thereto, in the sense that a multispecificpolypeptide of the invention may comprise at least one Nanobody againstOX40L, and any number of Nanobodies directed against one or moreantigens different from OX40L.

Furthermore, although it is encompassed within the scope of theinvention that the specific order or arrangement of the variousNanobodies in the polypeptides of the invention may have some influenceon the properties of the final polypeptide of the invention (includingbut not limited to the affinity, specificity or avidity for OX40L, oragainst the one or more other antigens), said order or arrangement isusually not critical and may be suitably chosen by the skilled person,optionally after some limited routine experiments based on thedisclosure herein. Thus, when reference is made to a specificmultivalent or multispecific polypeptide of the invention, it should benoted that this encompasses any order or arrangements of the relevantNanobodies, unless explicitly indicated otherwise.

Finally, it is also within the scope of the invention that thepolypeptides of the invention contain two or more Nanobodies and one ormore further amino acid sequences (as mentioned herein).

For multivalent and multispecific polypeptides containing one or moreV_(HH) domains and their preparation, reference is also made to Conrathet al., J. Biol. Chem., Vol. 276, 10. 7346-7350, 2001; Muyldermans,Reviews in Molecular Biotechnology 74 (2001), 277-302; as well as to forexample WO 96/34103 and WO 99/23221. Some other examples of somespecific multispecific and/or multivalent polypeptide of the inventioncan be found in the applications by Ablynx N.V. referred to herein.

One preferred, but non-limiting example of a multispecific polypeptideof the invention comprises at least one Nanobody of the invention and atleast one Nanobody that provides for an increased half-life. SuchNanobodies may for example be Nanobodies that are directed against aserum protein, and in particular a human serum protein, such as humanserum albumin, thyroxine-binding protein, (human) transferrin,fibrinogen, an immunoglobulin such as IgG, IgE or IgM, or against one ofthe serum proteins listed in WO 04/003019. Of these, Nanobodies that canbind to serum albumin (and in particular human serum albumin) or to IgG(and in particular human IgG, see for example Nanobody VH-1 described inthe review by Muyldermans, supra) are particularly preferred (althoughfor example, for experiments in mice or primates, Nanobodies against orcross-reactive with mouse serum albumin (MSA) or serum albumin from saidprimate, respectively, can be used. However, for pharmaceutical use,Nanobodies against human serum albumin or human IgG will usually bepreferred). Nanobodies that provide for increased half-life and that canbe used in the polypeptides of the invention include the Nanobodiesdirected against serum albumin that are described in WO 04/041865, in WO06/122787 and in the further patent applications by Ablynx N.V., such asthose mentioned above.

For example, the some preferred Nanobodies that provide for increasedhalf-life for use in the present invention include Nanobodies that canbind to amino acid residues on (human) serum albumin that are notinvolved in binding of serum albumin to FcRn (see for example WO06/0122787); Nanobodies that are capable of binding to amino acidresidues on serum albumin that do not form part of domain Ill of serumalbumin (see for example WO 06/0122787); Nanobodies that have or canprovide an increased half-life (see for example WO 08/028977 by AblynxN.V mentioned herein); Nanobodies against human serum albumin that arecross-reactive with serum albumin from at least one species of mammal,and in particular with at least one species of primate (such as, withoutlimitation, monkeys from the genus Macaca (such as, and in particular,cynomolgus monkeys (Macaca fascicularis) and/or rhesus monkeys (Macacamulatta)) and baboon (Papio ursinus)) (see for example WO 08/028977 byAblynx N.V)); Nanobodies that can bind to serum albumin in a pHindependent manner (see for example WO2008/043821 by Ablynx N.V.mentioned herein) and/or Nanobodies that are conditional binders (seefor example WO 08/043822 by Ablynx N.V.).

Some particularly preferred Nanobodies that provide for increasedhalf-life and that can be used in the polypeptides of the inventioninclude the Nanobodies ALB-1 to ALB-10 disclosed in WO 06/122787 (seeTables II and III) of which ALB-8 (SEQ ID NO: 62 in WO 06/122787) isparticularly preferred.

Some preferred, but non-limiting examples of polypeptides of theinvention that comprise at least one Nanobody of the invention and atleast one Nanobody that provides for increased half-life are given inSEQ ID NO's 186 to 198 and 227 to 234.

According to a specific, but non-limiting aspect of the invention, thepolypeptides of the invention contain, besides the one or moreNanobodies of the invention, at least one Nanobody against human serumalbumin.

Generally, any polypeptides of the invention with increased half-lifethat contain one or more Nanobodies of the invention, and anyderivatives of Nanobodies of the invention or of such polypeptides thathave an increased half-life, preferably have a half-life that is atleast 1.5 times, preferably at least 2 times, such as at least 5 times,for example at least 10 times or more than 20 times, greater than thehalf-life of the corresponding Nanobody of the invention per se. Forexample, such a derivative or polypeptides with increased half-life mayhave a half-life that is increased with more than 1 hours, preferablymore than 2 hours, more preferably more than 6 hours, such as more than12 hours, or even more than 24, 48 or 72 hours, compared to thecorresponding Nanobody of the invention per se.

In a preferred, but non-limiting aspect of the invention, suchderivatives or polypeptides may exhibit a serum half-life in human of atleast about 12 hours, preferably at least 24 hours, more preferably atleast 48 hours, even more preferably at least 72 hours or more. Forexample, such derivatives or polypeptides may have a half-life of atleast 5 days (such as about 5 to 10 days), preferably at least 9 days(such as about 9 to 14 days), more preferably at least about 10 days(such as about 10 to 15 days), or at least about 11 days (such as about11 to 16 days), more preferably at least about 12 days (such as about 12to 18 days or more), or more than 14 days (such as about 14 to 19 days).

According to one aspect of the invention the polypeptides are capable ofbinding to one or more molecules which can increase the half-life of thepolypeptide in vivo.

The polypeptides of the invention are stabilised in vivo and theirhalf-life increased by binding to molecules which resist degradationand/or clearance or sequestration. Typically, such molecules arenaturally occurring proteins which themselves have a long half-life invivo.

Another preferred, but non-limiting example of a multispecificpolypeptide of the invention comprises at least one Nanobody of theinvention and at least one Nanobody that directs the polypeptide of theinvention towards, and/or that allows the polypeptide of the inventionto penetrate or to enter into specific organs, tissues, cells, or partsor compartments of cells, and/or that allows the Nanobody to penetrateor cross a biological barrier such as a cell membrane, a cell layer suchas a layer of epithelial cells, a tumor including solid tumors, or theblood-brain-barrier. Examples of such Nanobodies include Nanobodies thatare directed towards specific cell-surface proteins, markers or epitopesof the desired organ, tissue or cell (for example cell-surface markersassociated with tumor cells), and the single-domain brain targetingantibody fragments described in WO 02/057445 and WO 06/040153, of whichFC44 (SEQ ID NO: 189 of WO 06/040153) and FC5 (SEQ ID NO: 190 of WO06/040154) are preferred examples.

In the polypeptides of the invention, the one or more Nanobodies and theone or more polypeptides may be directly linked to each other (as forexample described in WO 99/23221) and/or may be linked to each other viaone or more suitable spacers or linkers, or any combination thereof.

Suitable spacers or linkers for use in multivalent and multispecificpolypeptides will be clear to the skilled person, and may generally beany linker or spacer used in the art to link amino acid sequences.Preferably, said linker or spacer is suitable for use in constructingproteins or polypeptides that are intended for pharmaceutical use.

Some particularly preferred spacers include the spacers and linkers thatare used in the art to link antibody fragments or antibody domains.These include the linkers mentioned in the general background art citedabove, as well as for example linkers that are used in the art toconstruct diabodies or ScFv fragments (in this respect, however, itsshould be noted that, whereas in diabodies and in ScFv fragments, thelinker sequence used should have a length, a degree of flexibility andother properties that allow the pertinent V_(H) and V_(L) domains tocome together to form the complete antigen-binding site, there is noparticular limitation on the length or the flexibility of the linkerused in the polypeptide of the invention, since each Nanobody by itselfforms a complete antigen-binding site).

For example, a linker may be a suitable amino acid sequence, and inparticular amino acid sequences of between 1 and 50, preferably between1 and 30, such as between 1 and 10 amino acid residues. Some preferredexamples of such amino acid sequences include gly-ser linkers, forexample of the type (gly_(x)ser_(y))_(z), such as (for example(gly₄ser)₃ or (gly₃ser₂)₃, as described in WO 99/42077 and the GS30,GS15, GS9 and GS7 linkers described in the applications by Ablynxmentioned herein (see for example WO 06/040153 and WO 06/122825), aswell as hinge-like regions, such as the hinge regions of naturallyoccurring heavy chain antibodies or similar sequences (such as describedin WO 94/04678).

Some other particularly preferred linkers are poly-alanine (such asAAA), as well as the linkers GS30 (SEQ ID NO: 85 in WO 06/122825) andGS9 (SEQ ID NO: 84 in WO 06/122825).

Other suitable linkers generally comprise organic compounds or polymers,in particular those suitable for use in proteins for pharmaceutical use.For instance, poly(ethyleneglycol) moieties have been used to linkantibody domains, see for example WO 04/081026.

It is encompassed within the scope of the invention that the length, thedegree of flexibility and/or other properties of the linker(s) used(although not critical, as it usually is for linkers used in ScFvfragments) may have some influence on the properties of the finalpolypeptide of the invention, including but not limited to the affinity,specificity or avidity for OX40L, or for one or more of the otherantigens. Based on the disclosure herein, the skilled person will beable to determine the optimal linker(s) for use in a specificpolypeptide of the invention, optionally after some limited routineexperiments.

For example, in multivalent polypeptides of the invention that compriseNanobodies directed against a multimeric antigen (such as a multimericreceptor or other protein), the length and flexibility of the linker arepreferably such that it allows each Nanobody of the invention present inthe polypeptide to bind to the antigenic determinant on each of thesubunits of the multimer. Similarly, in a multispecific polypeptide ofthe invention that comprises Nanobodies directed against two or moredifferent antigenic determinants on the same antigen (for exampleagainst different epitopes of an antigen and/or against differentsubunits of a multimeric receptor, channel or protein), the length andflexibility of the linker are preferably such that it allows eachNanobody to bind to its intended antigenic determinant. Again, based onthe disclosure herein, the skilled person will be able to determine theoptimal linker(s) for use in a specific polypeptide of the invention,optionally after some limited routine experiments.

It is also within the scope of the invention that the linker(s) usedconfer one or more other favourable properties or functionality to thepolypeptides of the invention, and/or provide one or more sites for theformation of derivatives and/or for the attachment of functional groups(e.g. as described herein for the derivatives of the Nanobodies of theinvention). For example, linkers containing one or more charged aminoacid residues (see Table A-2 on page 48 of the International applicationWO 08/020079) can provide improved hydrophilic properties, whereaslinkers that form or contain small epitopes or tags can be used for thepurposes of detection, identification and/or purification. Again, basedon the disclosure herein, the skilled person will be able to determinethe optimal linkers for use in a specific polypeptide of the invention,optionally after some limited routine experiments.

Finally, when two or more linkers are used in the polypeptides of theinvention, these linkers may be the same or different. Again, based onthe disclosure herein, the skilled person will be able to determine theoptimal linkers for use in a specific polypeptide of the invention,optionally after some limited routine experiments.

Usually, for easy of expression and production, a polypeptide of theinvention will be a linear polypeptide. However, the invention in itsbroadest sense is not limited thereto. For example, when a polypeptideof the invention comprises three of more Nanobodies, it is possible tolink them by use of a linker with three or more “arms”, which each “arm”being linked to a Nanobody, so as to provide a “star-shaped” construct.It is also possible, although usually less preferred, to use circularconstructs.

The invention also comprises derivatives of the polypeptides of theinvention, which may be essentially analogous to the derivatives of theNanobodies of the invention, i.e. as described herein.

The invention also comprises proteins or polypeptides that “essentiallyconsist” of a polypeptide of the invention (in which the wording“essentially consist of” has essentially the same meaning as indicatedhereinabove).

According to one aspect of the invention, the polypeptide of theinvention is in essentially isolated from, as defined herein.

The amino acid sequences, Nanobodies, polypeptides and nucleic acids ofthe invention can be prepared in a manner known per se, as will be clearto the skilled person from the further description herein. For example,the Nanobodies and polypeptides of the invention can be prepared in anymanner known per se for the preparation of antibodies and in particularfor the preparation of antibody fragments (including but not limited to(single) domain antibodies and ScFv fragments). Some preferred, butnon-limiting methods for preparing the amino acid sequences, Nanobodies,polypeptides and nucleic acids include the methods and techniquesdescribed herein.

As will be clear to the skilled person, one particularly useful methodfor preparing an amino acid sequence, Nanobody and/or a polypeptide ofthe invention generally comprises the steps of:

-   i) the expression, in a suitable host cell or host organism (also    referred to herein as a “host of the invention”) or in another    suitable expression system of a nucleic acid that encodes said amino    acid sequence, Nanobody or polypeptide of the invention (also    referred to herein as a “nucleic acid of the invention”), optionally    followed by:-   ii) isolating and/or purifying the amino acid sequence, Nanobody or    polypeptide of the invention thus obtained.

In particular, such a method may comprise the steps of:

-   i) cultivating and/or maintaining a host of the invention under    conditions that are such that said host of the invention expresses    and/or produces at least one amino acid sequence, Nanobody and/or    polypeptide of the invention; optionally followed by:-   ii) isolating and/or purifying the amino acid sequence, Nanobody or    polypeptide of the invention thus obtained.

A nucleic acid of the invention can be in the form of single or doublestranded DNA or RNA, and is preferably in the form of double strandedDNA. For example, the nucleotide sequences of the invention may begenomic DNA, cDNA or synthetic DNA (such as DNA with a codon usage thathas been specifically adapted for expression in the intended host cellor host organism).

According to one aspect of the invention, the nucleic acid of theinvention is in essentially isolated from, as defined herein.

The nucleic acid of the invention may also be in the form of, be presentin and/or be part of a vector, such as for example a plasmid, cosmid orYAC, which again may be in essentially isolated form.

The nucleic acids of the invention can be prepared or obtained in amanner known per se, based on the information on the amino acidsequences for the polypeptides of the invention given herein, and/or canbe isolated from a suitable natural source. To provide analogs,nucleotide sequences encoding naturally occurring V_(HH) domains can forexample be subjected to site-directed mutagenesis, so at to provide anucleic acid of the invention encoding said analog. Also, as will beclear to the skilled person, to prepare a nucleic acid of the invention,also several nucleotide sequences, such as at least one nucleotidesequence encoding a Nanobody and for example nucleic acids encoding oneor more linkers can be linked together in a suitable manner.

Techniques for generating the nucleic acids of the invention will beclear to the skilled person and may for instance include, but are notlimited to, automated DNA synthesis; site-directed mutagenesis;combining two or more naturally occurring and/or synthetic sequences (ortwo or more parts thereof), introduction of mutations that lead to theexpression of a truncated expression product; introduction of one ormore restriction sites (e.g. to create cassettes and/or regions that mayeasily be digested and/or ligated using suitable restriction enzymes),and/or the introduction of mutations by means of a PCR reaction usingone or more “mismatched” primers, using for example a sequence of anaturally occurring form of OX40L as a template. These and othertechniques will be clear to the skilled person, and reference is againmade to the standard handbooks, such as Sambrook et al. and Ausubel etal., mentioned above, as well as the Examples below.

The nucleic acid of the invention may also be in the form of, be presentin and/or be part of a genetic construct, as will be clear to the personskilled in the art and as described on pages 131-134 of WO 08/020079(incorporated herein by reference). Such genetic constructs generallycomprise at least one nucleic acid of the invention that is optionallylinked to one or more elements of genetic constructs known per se, suchas for example one or more suitable regulatory elements (such as asuitable promoter(s), enhancer(s), terminator(s), etc.) and the furtherelements of genetic constructs referred to herein. Such geneticconstructs comprising at least one nucleic acid of the invention willalso be referred to herein as “genetic constructs of the invention”.

The genetic constructs of the invention may be DNA or RNA, and arepreferably double-stranded DNA. The genetic constructs of the inventionmay also be in a form suitable for transformation of the intended hostcell or host organism, in a form suitable for integration into thegenomic DNA of the intended host cell or in a form suitable forindependent replication, maintenance and/or inheritance in the intendedhost organism. For instance, the genetic constructs of the invention maybe in the form of a vector, such as for example a plasmid, cosmid, YAC,a viral vector or transposon. In particular, the vector may be anexpression vector, i.e. a vector that can provide for expression invitro and/or in vivo (e.g. in a suitable host cell, host organism and/orexpression system).

In a preferred but non-limiting aspect, a genetic construct of theinvention comprises

-   i) at least one nucleic acid of the invention; operably connected to-   ii) one or more regulatory elements, such as a promoter and    optionally a suitable terminator;    and optionally also-   iii) one or more further elements of genetic constructs known per    se;

in which the terms “operably connected” and “operably linked” have themeaning given on pages 131-134 of WO 08/020079; and in which the“regulatory elements”, “promoter”, “terminator” and “further elements”are as described on pages 131-134 of WO 08/020079; and in which thegenetic constructs may further be as described on pages 131-134 of WO08/020079.

The nucleic acids of the invention and/or the genetic constructs of theinvention may be used to transform a host cell or host organism, i.e.for expression and/or production of the amino acid sequence, Nanobody orpolypeptide of the invention. Suitable hosts or host cells will be clearto the skilled person, and may for example be any suitable fungal,prokaryotic or eukaryotic cell or cell line or any suitable fungal,prokaryotic or eukaryotic organism, for example those described on pages134 and 135 of WO 08/020079; as well as all other hosts or host cellsknown per se for the expression and production of antibodies andantibody fragments (including but not limited to (single) domainantibodies and ScFv fragments), which will be clear to the skilledperson. Reference is also made to the general background art citedhereinabove, as well as to for example WO 94/29457; WO 96/34103; WO99/42077; Frenken et al., (1998), supra; Riechmann and Muyldermans,(1999), supra; van der Linden, (2000), supra; Thomassen et al., (2002),supra; Joosten et al., (2003), supra; Joosten et al., (2005), supra; andthe further references cited herein.

The amino acid sequences, Nanobodies and polypeptides of the inventioncan also be introduced and expressed in one or more cells, tissues ororgans of a multicellular organism, for example for prophylactic and/ortherapeutic purposes (e.g. as a gene therapy), as further described onpages 135 and 136 of in WO 08/020079 and in the further references citedin WO 08/020079.

For expression of the Nanobodies in a cell, they may also be expressedas so-called “intrabodies”, as for example described in WO 94/02610, WO95/22618 and U.S. Pat. No. 7,004,940; WO 03/014960; in Cattaneo, A. &Biocca, S. (1997) Intracellular Antibodies: Development andApplications. Landes and Springer-Verlag; and in Kontermann, Methods 34,(2004), 163-170.

The amino acid sequences, Nanobodies and polypeptides of the inventioncan for example also be produced in the milk of transgenic mammals, forexample in the milk of rabbits, cows, goats or sheep (see for exampleU.S. Pat. No. 6,741,957, U.S. Pat. No. 6,304,489 and U.S. Pat. No.6,849,992 for general techniques for introducing transgenes intomammals), in plants or parts of plants including but not limited totheir leaves, flowers, fruits, seed, roots or tubers (for example intobacco, maize, soybean or alfalfa) or in for example pupae of thesilkworm Bombix mori.

Furthermore, the amino acid sequences, Nanobodies and polypeptides ofthe invention can also be expressed and/or produced in cell-freeexpression systems, and suitable examples of such systems will be clearto the skilled person. Some preferred, but non-limiting examples includeexpression in the wheat germ system; in rabbit reticulocyte lysates; orin the E. coli Zubay system.

As mentioned above, one of the advantages of the use of Nanobodies isthat the polypeptides based thereon can be prepared through expressionin a suitable bacterial system, and suitable bacterial expressionsystems, vectors, host cells, regulatory elements, etc., will be clearto the skilled person, for example from the references cited above. Itshould however be noted that the invention in its broadest sense is notlimited to expression in bacterial systems.

Preferably, in the invention, an (in vivo or in vitro) expressionsystem, such as a bacterial expression system, is used that provides thepolypeptides of the invention in a form that is suitable forpharmaceutical use, and such expression systems will again be clear tothe skilled person. As also will be clear to the skilled person,polypeptides of the invention suitable for pharmaceutical use can beprepared using techniques for peptide synthesis.

For production on industrial scale, preferred heterologous hosts for the(industrial) production of Nanobodies or Nanobody-containing proteintherapeutics include strains of E. coli, Pichia pastoris, S. cerevisiaethat are suitable for large scale expression/production/fermentation,and in particular for large scale pharmaceutical (i.e. GMP grade)expression/production/fermentation. Suitable examples of such strainswill be clear to the skilled person. Such strains andproduction/expression systems are also made available by companies suchas Biovitrum (Uppsala, Sweden).

Alternatively, mammalian cell lines, in particular Chinese hamster ovary(CHO) cells, can be used for large scaleexpression/production/fermentation, and in particular for large scalepharmaceutical expression/production/fermentation. Again, suchexpression/production systems are also made available by some of thecompanies mentioned above.

The choice of the specific expression system would depend in part on therequirement for certain post-translational modifications, morespecifically glycosylation. The production of a Nanobody-containingrecombinant protein for which glycosylation is desired or required wouldnecessitate the use of mammalian expression hosts that have the abilityto glycosylate the expressed protein. In this respect, it will be clearto the skilled person that the glycosylation pattern obtained (i.e. thekind, number and position of residues attached) will depend on the cellor cell line that is used for the expression. Preferably, either a humancell or cell line is used (i.e. leading to a protein that essentiallyhas a human glycosylation pattern) or another mammalian cell line isused that can provide a glycosylation pattern that is essentially and/orfunctionally the same as human glycosylation or at least mimics humanglycosylation. Generally, prokaryotic hosts such as E. coli do not havethe ability to glycosylate proteins, and the use of lower eukaryotessuch as yeast usually leads to a glycosylation pattern that differs fromhuman glycosylation. Nevertheless, it should be understood that all theforegoing host cells and expression systems can be used in theinvention, depending on the desired amino acid sequence, Nanobody orpolypeptide to be obtained.

Thus, according to one non-limiting aspect of the invention, the aminoacid sequence, Nanobody or polypeptide of the invention is glycosylated.According to another non-limiting aspect of the invention, the aminoacid sequence, Nanobody or polypeptide of the invention isnon-glycosylated.

According to one preferred, but non-limiting aspect of the invention,the amino acid sequence, Nanobody or polypeptide of the invention isproduced in a bacterial cell, in particular a bacterial cell suitablefor large scale pharmaceutical production, such as cells of the strainsmentioned above.

According to another preferred, but non-limiting aspect of theinvention, the amino acid sequence, Nanobody or polypeptide of theinvention is produced in a yeast cell, in particular a yeast cellsuitable for large scale pharmaceutical production, such as cells of thespecies mentioned above.

According to yet another preferred, but non-limiting aspect of theinvention, the amino acid sequence, Nanobody or polypeptide of theinvention is produced in a mammalian cell, in particular in a human cellor in a cell of a human cell line, and more in particular in a humancell or in a cell of a human cell line that is suitable for large scalepharmaceutical production, such as the cell lines mentioned hereinabove.

As further described on pages 138 and 139 of WO 08/020079, whenexpression in a host cell is used to produce the amino acid sequences,Nanobodies and the polypeptides of the invention, the amino acidsequences, Nanobodies and polypeptides of the invention can be producedeither intracellullarly (e.g. in the cytosol, in the periplasma or ininclusion bodies) and then isolated from the host cells and optionallyfurther purified; or can be produced extracellularly (e.g. in the mediumin which the host cells are cultured) and then isolated from the culturemedium and optionally further purified. Thus, according to onenon-limiting aspect of the invention, the amino acid sequence, Nanobodyor polypeptide of the invention is an amino acid sequence, Nanobody orpolypeptide that has been produced intracellularly and that has beenisolated from the host cell, and in particular from a bacterial cell orfrom an inclusion body in a bacterial cell. According to anothernon-limiting aspect of the invention, the amino acid sequence, Nanobodyor polypeptide of the invention is an amino acid sequence, Nanobody orpolypeptide that has been produced extracellularly, and that has beenisolated from the medium in which the host cell is cultivated.

Some preferred, but non-limiting promoters for use with these host cellsinclude those mentioned on pages 139 and 140 of WO 08/020079.

Some preferred, but non-limiting secretory sequences for use with thesehost cells include those mentioned on page 140 of WO 08/020079.

Suitable techniques for transforming a host or host cell of theinvention will be clear to the skilled person and may depend on theintended host cell/host organism and the genetic construct to be used.Reference is again made to the handbooks and patent applicationsmentioned above.

After transformation, a step for detecting and selecting those hostcells or host organisms that have been successfully transformed with thenucleotide sequence/genetic construct of the invention may be performed.This may for instance be a selection step based on a selectable markerpresent in the genetic construct of the invention or a step involvingthe detection of the amino acid sequence of the invention, e.g. usingspecific antibodies.

The transformed host cell (which may be in the form or a stable cellline) or host organisms (which may be in the form of a stable mutantline or strain) form further aspects of the present invention.

Preferably, these host cells or host organisms are such that theyexpress, or are (at least) capable of expressing (e.g. under suitableconditions), an amino acid sequence, Nanobody or polypeptide of theinvention (and in case of a host organism: in at least one cell, part,tissue or organ thereof). The invention also includes furthergenerations, progeny and/or offspring of the host cell or host organismof the invention, that may for instance be obtained by cell division orby sexual or asexual reproduction.

To produce/obtain expression of the amino acid sequences of theinvention, the transformed host cell or transformed host organism maygenerally be kept, maintained and/or cultured under conditions such thatthe (desired) amino acid sequence, Nanobody or polypeptide of theinvention is expressed/produced. Suitable conditions will be clear tothe skilled person and will usually depend upon the host cell/hostorganism used, as well as on the regulatory elements that control theexpression of the (relevant) nucleotide sequence of the invention.Again, reference is made to the handbooks and patent applicationsmentioned above in the paragraphs on the genetic constructs of theinvention.

Generally, suitable conditions may include the use of a suitable medium,the presence of a suitable source of food and/or suitable nutrients, theuse of a suitable temperature, and optionally the presence of a suitableinducing factor or compound (e.g. when the nucleotide sequences of theinvention are under the control of an inducible promoter); all of whichmay be selected by the skilled person. Again, under such conditions, theamino acid sequences of the invention may be expressed in a constitutivemanner, in a transient manner, or only when suitably induced.

It will also be clear to the skilled person that the amino acidsequence, Nanobody or polypeptide of the invention may (first) begenerated in an immature form (as mentioned above), which may then besubjected to post-translational modification, depending on the hostcell/host organism used. Also, the amino acid sequence, Nanobody orpolypeptide of the invention may be glycosylated, again depending on thehost cell/host organism used.

The amino acid sequence, Nanobody or polypeptide of the invention maythen be isolated from the host cell/host organism and/or from the mediumin which said host cell or host organism was cultivated, using proteinisolation and/or purification techniques known per se, such as(preparative) chromatography and/or electrophoresis techniques,differential precipitation techniques, affinity techniques (e.g. using aspecific, cleavable amino acid sequence fused with the amino acidsequence, Nanobody or polypeptide of the invention) and/or preparativeimmunological techniques (i.e. using antibodies against the amino acidsequence to be isolated).

Generally, for pharmaceutical use, the polypeptides of the invention maybe formulated as a pharmaceutical preparation or compositions comprisingat least one polypeptide of the invention and at least onepharmaceutically acceptable carrier, diluent or excipient and/oradjuvant, and optionally one or more further pharmaceutically activepolypeptides and/or compounds. By means of non-limiting examples, such aformulation may be in a form suitable for oral administration, forparenteral administration (such as by intravenous, intramuscular orsubcutaneous injection or intravenous infusion), for topicaladministration, for administration by inhalation, by a skin patch, by animplant, by a suppository, etc. Such suitable administration forms—whichmay be solid, semi-solid or liquid, depending on the manner ofadministration—as well as methods and carriers for use in thepreparation thereof, will be clear to the skilled person, and arefurther described herein.

Thus, in a further aspect, the invention relates to a pharmaceuticalcomposition that contains at least one amino acid of the invention, atleast one Nanobody of the invention or at least one polypeptide of theinvention and at least one suitable carrier, diluent or excipient (i.e.suitable for pharmaceutical use), and optionally one or more furtheractive substances.

Generally, the amino acid sequences, Nanobodies and polypeptides of theinvention can be formulated and administered in any suitable mannerknown per se, for which reference is for example made to the generalbackground art cited above (and in particular to WO 04/041862, WO04/041863, WO 04/041865, WO 04/041867 and WO 08/020079) as well as tothe standard handbooks, such as Remington's Pharmaceutical Sciences,18^(th) Ed., Mack Publishing Company, USA (1990), Remington, the Scienceand Practice of Pharmacy, 21st Edition, Lippincott Williams and Wilkins(2005); or the Handbook of Therapeutic Antibodies (S. Dubel, Ed.),Wiley, Weinheim, 2007 (see for example pages 252-255).

For example, the amino acid sequences, Nanobodies and polypeptides ofthe invention may be formulated and administered in any manner known perse for conventional antibodies and antibody fragments (including ScFv'sand diabodies) and other pharmaceutically active proteins. Suchformulations and methods for preparing the same will be clear to theskilled person, and for example include preparations suitable forparenteral administration (for example intravenous, intraperitoneal,subcutaneous, intramuscular, intraluminal, intra-arterial or intrathecaladministration) or for topical (i.e. transdermal or intradermal)administration.

Preparations for parenteral administration may for example be sterilesolutions, suspensions, dispersions or emulsions that are suitable forinfusion or injection. Suitable carriers or diluents for suchpreparations for example include, without limitation, those mentioned onpage 143 of WO 08/020079. Usually, aqueous solutions or suspensions willbe preferred.

The amino acid sequences, Nanobodies and polypeptides of the inventioncan also be administered using gene therapy methods of delivery. See,e.g., U.S. Pat. No. 5,399,346, which is incorporated by reference in itsentirety. Using a gene therapy method of delivery, primary cellstransfected with the gene encoding an amino acid sequence, Nanobody orpolypeptide of the invention can additionally be transfected with tissuespecific promoters to target specific organs, tissue, grafts, tumors, orcells and can additionally be transfected with signal and stabilizationsequences for subcellularly localized expression.

Thus, the amino acid sequences, Nanobodies and polypeptides of theinvention may be systemically administered, e.g., orally, in combinationwith a pharmaceutically acceptable vehicle such as an inert diluent oran assimilable edible carrier. They may be enclosed in hard or softshell gelatin capsules, may be compressed into tablets, or may beincorporated directly with the food of the patient's diet. For oraltherapeutic administration, the amino acid sequences, Nanobodies andpolypeptides of the invention may be combined with one or moreexcipients and used in the form of ingestible tablets, buccal tablets,troches, capsules, elixirs, suspensions, syrups, wafers, and the like.Such compositions and preparations should contain at least 0.1% of theamino acid sequence, Nanobody or polypeptide of the invention. Theirpercentage in the compositions and preparations may, of course, bevaried and may conveniently be between about 2 to about 60% of theweight of a given unit dosage form. The amount of the amino acidsequence, Nanobody or polypeptide of the invention in suchtherapeutically useful compositions is such that an effective dosagelevel will be obtained.

The tablets, troches, pills, capsules, and the like may also containbinders, excipients, disintegrating agents, lubricants and sweetening orflavouring agents, for example those mentioned on pages 143-144 of WO08/020079. When the unit dosage form is a capsule, it may contain, inaddition to materials of the above type, a liquid carrier, such as avegetable oil or a polyethylene glycol. Various other materials may bepresent as coatings or to otherwise modify the physical form of thesolid unit dosage form. For instance, tablets, pills, or capsules may becoated with gelatin, wax, shellac or sugar and the like. A syrup orelixir may contain the amino acid sequences, Nanobodies and polypeptidesof the invention, sucrose or fructose as a sweetening agent, methyl andpropylparabens as preservatives, a dye and flavoring such as cherry ororange flavor. Of course, any material used in preparing any unit dosageform should be pharmaceutically acceptable and substantially non-toxicin the amounts employed. In addition, the amino acid sequences,Nanobodies and polypeptides of the invention may be incorporated intosustained-release preparations and devices.

Preparations and formulations for oral administration may also beprovided with an enteric coating that will allow the constructs of theinvention to resist the gastric environment and pass into theintestines. More generally, preparations and formulations for oraladministration may be suitably formulated for delivery into any desiredpart of the gastrointestinal tract. In addition, suitable suppositoriesmay be used for delivery into the gastrointestinal tract.

The amino acid sequences, Nanobodies and polypeptides of the inventionmay also be administered intravenously or intraperitoneally by infusionor injection, as further described on pages 144 and 145 of WO 08/020079.

For topical administration, the amino acid sequences, Nanobodies andpolypeptides of the invention may be applied in pure form, i.e., whenthey are liquids. However, it will generally be desirable to administerthem to the skin as compositions or formulations, in combination with adermatologically acceptable carrier, which may be a solid or a liquid,as further described on page 145 of WO 08/020079.

Generally, the concentration of the amino acid sequences, Nanobodies andpolypeptides of the invention in a liquid composition, such as a lotion,will be from about 0.1-25 wt-%, preferably from about 0.5-10 wt-%. Theconcentration in a semi-solid or solid composition such as a gel or apowder will be about 0.1-5 wt-%, preferably about 0.5-2.5 wt-%.

The amount of the amino acid sequences, Nanobodies and polypeptides ofthe invention required for use in treatment will vary not only with theparticular amino acid sequence, Nanobody or polypeptide selected butalso with the route of administration, the nature of the condition beingtreated and the age and condition of the patient and will be ultimatelyat the discretion of the attendant physician or clinician. Also thedosage of the amino acid sequences, Nanobodies and polypeptides of theinvention varies depending on the target cell, tumor, tissue, graft, ororgan.

The desired dose may conveniently be presented in a single dose or asdivided doses administered at appropriate intervals, for example, astwo, three, four or more sub-doses per day. The sub-dose itself may befurther divided, e.g., into a number of discrete loosely spacedadministrations; such as multiple inhalations from an insufflator or byapplication of a plurality of drops into the eye.

An administration regimen could include long-term, daily treatment. By“long-term” is meant at least two weeks and preferably, several weeks,months, or years of duration. Necessary modifications in this dosagerange may be determined by one of ordinary skill in the art using onlyroutine experimentation given the teachings herein. See Remington'sPharmaceutical Sciences (Martin, E. W., ed. 4), Mack Publishing Co.,Easton, Pa. The dosage can also be adjusted by the individual physicianin the event of any complication.

In another aspect, the invention relates to a method for the preventionand/or treatment of at least one inflammatory disease and/or disordersuch as e.g. asthma and/or allergic asthma, said method comprisingadministering, to a subject in need thereof, a pharmaceutically activeamount of an amino acid sequence of the invention, of a Nanobody of theinvention, of a polypeptide of the invention, and/or of a pharmaceuticalcomposition comprising the same.

In the context of the present invention, the term “prevention and/ortreatment” not only comprises preventing and/or treating the disease,but also generally comprises preventing the onset of the disease,slowing or reversing the progress of disease, preventing or slowing theonset of one or more symptoms associated with the disease, reducingand/or alleviating one or more symptoms associated with the disease,reducing the severity and/or the duration of the disease and/or of anysymptoms associated therewith and/or preventing a further increase inthe severity of the disease and/or of any symptoms associated therewith,preventing, reducing or reversing any physiological damage caused by thedisease, and generally any pharmacological action that is beneficial tothe patient being treated.

The subject to be treated may be any warm-blooded animal, but is inparticular a mammal, and more in particular a human being. As will beclear to the skilled person, the subject to be treated will inparticular be a person suffering from, or at risk of, the diseases anddisorders mentioned herein.

The invention relates to a method for the prevention and/or treatment ofat least one disease and/or disorder that is associated with OX40L, withits biological or pharmacological activity, and/or with the biologicalpathways or signalling in which OX40L is involved, said methodcomprising administering, to a subject in need thereof, apharmaceutically active amount of an amino acid sequence of theinvention, of a Nanobody of the invention, of a polypeptide of theinvention, and/or of a pharmaceutical composition comprising the same.In particular, the invention relates to a method for the preventionand/or treatment of at least one disease or disorder that can be treatedby modulating OX40L, its biological or pharmacological activity, and/orthe biological pathways or signalling in which OX40L is involved, saidmethod comprising administering, to a subject in need thereof, apharmaceutically active amount of an amino acid sequence of theinvention, of a Nanobody of the invention, of a polypeptide of theinvention, and/or of a pharmaceutical composition comprising the same.In particular, said pharmaceutically effective amount may be an amountthat is sufficient to modulate OX40L, its biological or pharmacologicalactivity, and/or the biological pathways or signalling in which OX40L isinvolved; and/or an amount that provides a level of the amino acidsequence of the invention, of a Nanobody of the invention, of apolypeptide of the invention in the circulation that is sufficient tomodulate OX40L, its biological or pharmacological activity, and/or thebiological pathways or signalling in which OX40L is involved.

The invention furthermore relates to a method for the prevention and/ortreatment of at least one disease or disorder that can be preventedand/or treated by administering an amino acid sequence of the invention,a Nanobody of the invention or a polypeptide of the invention to apatient, said method comprising administering, to a subject in needthereof, a pharmaceutically active amount of an amino acid sequence ofthe invention, of a Nanobody of the invention, of a polypeptide of theinvention, and/or of a pharmaceutical composition comprising the same.

More in particular, the invention relates to a method for the preventionand/or treatment of at least one disease or disorder chosen from thegroup consisting of the diseases and disorders listed herein, saidmethod comprising administering, to a subject in need thereof, apharmaceutically active amount of an amino acid sequence of theinvention, of a Nanobody of the invention, of a polypeptide of theinvention, and/or of a pharmaceutical composition comprising the same.

In another aspect, the invention relates to a method for immunotherapy,and in particular for passive immunotherapy, which method comprisesadministering, to a subject suffering from or at risk of the diseasesand disorders mentioned herein, a pharmaceutically active amount of anamino acid sequence of the invention, of a Nanobody of the invention, ofa polypeptide of the invention, and/or of a pharmaceutical compositioncomprising the same.

In the above methods, the amino acid sequences, Nanobodies and/orpolypeptides of the invention and/or the compositions comprising thesame can be administered in any suitable manner, depending on thespecific pharmaceutical formulation or composition to be used. Thus, theamino acid sequences, Nanobodies and/or polypeptides of the inventionand/or the compositions comprising the same can for example beadministered orally, intraperitoneally (e.g. intravenously,subcutaneously, intramuscularly, or via any other route ofadministration that circumvents the gastrointestinal tract),intranasally, transdermally, topically, by means of a suppository, byinhalation, again depending on the specific pharmaceutical formulationor composition to be used. The clinician will be able to select asuitable route of administration and a suitable pharmaceuticalformulation or composition to be used in such administration, dependingon the disease or disorder to be prevented or treated and other factorswell known to the clinician.

The amino acid sequences, Nanobodies and/or polypeptides of theinvention and/or the compositions comprising the same are administeredaccording to a regime of treatment that is suitable for preventingand/or treating the disease or disorder to be prevented or treated. Theclinician will generally be able to determine a suitable treatmentregimen, depending on factors such as the disease or disorder to beprevented or treated, the severity of the disease to be treated and/orthe severity of the symptoms thereof, the specific amino acid sequence,Nanobody or polypeptide of the invention to be used, the specific routeof administration and pharmaceutical formulation or composition to beused, the age, gender, weight, diet, general condition of the patient,and similar factors well known to the clinician.

Generally, the treatment regimen will comprise the administration of oneor more amino acid sequences, Nanobodies and/or polypeptides of theinvention, or of one or more compositions comprising the same, in one ormore pharmaceutically effective amounts or doses. The specific amount(s)or doses to administered can be determined by the clinician, again basedon the factors cited above.

Generally, for the prevention and/or treatment of the diseases anddisorders mentioned herein and depending on the specific disease ordisorder to be treated, the potency of the specific amino acid sequence,Nanobody and polypeptide of the invention to be used, the specific routeof administration and the specific pharmaceutical formulation orcomposition used, the amino acid sequences, Nanobodies and polypeptidesof the invention will generally be administered in an amount between 1gram and 0.01 microgram per kg body weight per day, preferably between0.1 gram and 0.1 microgram per kg body weight per day, such as about 1,10, 100 or 1000 microgram per kg body weight per day, eithercontinuously (e.g. by infusion), as a single daily dose or as multipledivided doses during the day. The clinician will generally be able todetermine a suitable daily dose, depending on the factors mentionedherein. It will also be clear that in specific cases, the clinician maychoose to deviate from these amounts, for example on the basis of thefactors cited above and his expert judgment. Generally, some guidance onthe amounts to be administered can be obtained from the amounts usuallyadministered for comparable conventional antibodies or antibodyfragments against the same target administered via essentially the sameroute, taking into account however differences in affinity/avidity,efficacy, biodistribution, half-life and similar factors well known tothe skilled person.

Usually, in the above method, a single amino acid sequence, Nanobody orpolypeptide of the invention will be used. It is however within thescope of the invention to use two or more amino acid sequences,Nanobodies and/or polypeptides of the invention in combination.

The Nanobodies, amino acid sequences and polypeptides of the inventionmay also be used in combination with one or more furtherpharmaceutically active compounds or principles, i.e. as a combinedtreatment regimen, which may or may not lead to a synergistic effect.Again, the clinician will be able to select such further compounds orprinciples, as well as a suitable combined treatment regimen, based onthe factors cited above and his expert judgement.

In particular, the amino acid sequences, Nanobodies and polypeptides ofthe invention may be used in combination with other pharmaceuticallyactive compounds or principles that are or can be used for theprevention and/or treatment of the diseases and disorders cited herein,as a result of which a synergistic effect may or may not be obtained.Examples of such compounds and principles, as well as routes, methodsand pharmaceutical formulations or compositions for administering themwill be clear to the clinician.

When two or more substances or principles are to be used as part of acombined treatment regimen, they can be administered via the same routeof administration or via different routes of administration, atessentially the same time or at different times (e.g. essentiallysimultaneously, consecutively, or according to an alternating regime).When the substances or principles are to be administered simultaneouslyvia the same route of administration, they may be administered asdifferent pharmaceutical formulations or compositions or part of acombined pharmaceutical formulation or composition, as will be clear tothe skilled person.

Also, when two or more active substances or principles are to be used aspart of a combined treatment regimen, each of the substances orprinciples may be administered in the same amount and according to thesame regimen as used when the compound or principle is used on its own,and such combined use may or may not lead to a synergistic effect.However, when the combined use of the two or more active substances orprinciples leads to a synergistic effect, it may also be possible toreduce the amount of one, more or all of the substances or principles tobe administered, while still achieving the desired therapeutic action.This may for example be useful for avoiding, limiting or reducing anyunwanted side-effects that are associated with the use of one or more ofthe substances or principles when they are used in their usual amounts,while still obtaining the desired pharmaceutical or therapeutic effect.

The effectiveness of the treatment regimen used according to theinvention may be determined and/or followed in any manner known per sefor the disease or disorder involved, as will be clear to the clinician.The clinician will also be able, where appropriate and on a case-by-casebasis, to change or modify a particular treatment regimen, so as toachieve the desired therapeutic effect, to avoid, limit or reduceunwanted side-effects, and/or to achieve an appropriate balance betweenachieving the desired therapeutic effect on the one hand and avoiding,limiting or reducing undesired side effects on the other hand.

Generally, the treatment regimen will be followed until the desiredtherapeutic effect is achieved and/or for as long as the desiredtherapeutic effect is to be maintained. Again, this can be determined bythe clinician.

In another aspect, the invention relates to the use of an amino acidsequence, Nanobody or polypeptide of the invention in the preparation ofa pharmaceutical composition for prevention and/or treatment of at leastone inflammatory disease and/or disorder such as e.g. asthma and/orallergic asthma; and/or for use in one or more of the methods oftreatment mentioned herein.

The subject to be treated may be any warm-blooded animal, but is inparticular a mammal, and more in particular a human being. As will beclear to the skilled person, the subject to be treated will inparticular be a person suffering from, or at risk of, the diseasesand/or disorders mentioned herein.

The invention also relates to the use of an amino acid sequence,Nanobody or polypeptide of the invention in the preparation of apharmaceutical composition for the prevention and/or treatment of atleast one disease and/or disorder that can be prevented and/or treatedby administering an amino acid sequence, Nanobody or polypeptide of theinvention to a patient.

More in particular, the invention relates to the use of an amino acidsequence, Nanobody or polypeptide of the invention in the preparation ofa pharmaceutical composition for the prevention and/or treatment of oneor more inflammatory diseases and/or disorders such as e.g. asthmaand/or allergic asthma, and in particular for the prevention andtreatment of one or more of the diseases and/or disorders listed herein.

Again, in such a pharmaceutical composition, the one or more amino acidsequences, Nanobodies or polypeptides of the invention may also besuitably combined with one or more other active principles, such asthose mentioned herein.

Finally, although the use of the Nanobodies of the invention (as definedherein) and of the polypeptides of the invention is much preferred, itwill be clear that on the basis of the description herein, the skilledperson will also be able to design and/or generate, in an analogousmanner, other amino acid sequences and in particular (single) domainantibodies against OX40L, as well as polypeptides comprising such(single) domain antibodies.

For example, it will also be clear to the skilled person that it may bepossible to “graft” one or more of the CDR's mentioned above for theNanobodies of the invention onto such (single) domain antibodies orother protein scaffolds, including but not limited to human scaffolds ornon-immunoglobulin scaffolds. Suitable scaffolds and techniques for suchCDR grafting will be clear to the skilled person and are well known inthe art, see for example those mentioned in WO 08/020079. For example,techniques known per se for grafting mouse or rat CDR's onto humanframeworks and scaffolds can be used in an analogous manner to providechimeric proteins comprising one or more of the CDR's of the Nanobodiesof the invention and one or more human framework regions or sequences.

It should also be noted that, when the Nanobodies of the inventionscontain one or more other CDR sequences than the preferred CDR sequencesmentioned above, these CDR sequences can be obtained in any manner knownper se, for example using one or more of the techniques described in WO08/020079.

Further uses of the amino acid sequences, Nanobodies, polypeptides,nucleic acids, genetic constructs and hosts and host cells of theinvention will be clear to the skilled person based on the disclosureherein. For example, and without limitation, the amino acid sequences ofthe invention can be linked to a suitable carrier or solid support so asto provide a medium than can be used in a manner known per se to purifyOX40L from compositions and preparations comprising the same.Derivatives of the amino acid sequences of the invention that comprise asuitable detectable label can also be used as markers to determine(qualitatively or quantitatively) the presence of OX40L in a compositionor preparation or as a marker to selectively detect the presence ofOX40L on the surface of a cell or tissue (for example, in combinationwith suitable cell sorting techniques).

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, it being recognizedthat various modifications are possible within the scope of theinvention.

All of the references described herein are incorporated by reference, inparticular for the teaching that is referenced hereinabove.

The invention will now be further described by means of the followingnon-limiting preferred aspects, examples and figures:

Preferred Aspects:

-   Aspect A-1: An amino acid sequence that is directed against and/or    that can specifically bind to OX40L.-   Aspect A-2: An amino acid sequence according to aspect A-1, that is    in essentially isolated form.-   Aspect A-3: An amino acid sequence according to aspect A-1 or A-2,    for administration to a subject, wherein said amino acid sequence    does not naturally occur in said subject.-   Aspect A-4: An amino acid sequence that can specifically bind to    OX40L with a dissociation constant (K_(D)) of 10⁻⁵ to 10⁻¹²    moles/litre or less, and preferably 10⁻⁷ to 10⁻¹² moles/litre or    less and more preferably 10⁻⁸ to 10⁻¹² moles/litre or less. Such an    amino acid sequence may in particular be an amino acid sequence    according to any of the preceding aspects.-   Aspect A-5: An amino acid sequence that can specifically bind to    OX40L with a rate of association (k_(on)-rate) of between 10² M⁻¹s⁻¹    to about 10⁷ M⁻¹s⁻¹, preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹,    more preferably between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between    10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹. Such an amino acid sequence may in    particular be an amino acid sequence according to any of the    preceding aspects.-   Aspect A-6: An amino acid sequence that can specifically bind to    OX40L with a rate of dissociation (k_(off) rate) between 1 s⁻¹ and    10⁻⁶ s⁻¹, preferably between 10⁻² s⁻¹ and 10⁻⁶ s⁻¹, more preferably    between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as between 10⁻⁴ s⁻¹ and 10⁻⁶    s⁻¹. Such an amino acid sequence may in particular be an amino acid    sequence according to any of the preceding aspects.-   Aspect A-7: An amino acid sequence that can specifically bind to    OX40L with an affinity less than 500 nM, preferably less than 200    nM, more preferably less than 10 nM, such as less than 500 pM, even    more preferably less than 1 nM. Such an amino acid sequence may in    particular be an amino acid sequence according to any of the    preceding aspects.-   Aspect A-8: An amino acid sequence that can specifically bind to    OX40L and has an IC50 value in the alphascreen assay (e.g. as    defined herein) with 0.12 nM hOX40L and 0.2 nM OX40/Fc of less than    10 nM, preferably less than 1 nM, more preferably less than 500 pM,    even more preferably less than 1 nM, most preferred less than 100    pM. Such an amino acid sequence may in particular be an amino acid    sequence according to any of the preceding aspects.-   Aspect A-9: An amino acid sequence that can specifically bind to    OX40L and has an IC50 value in the FACS assay (e.g. as defined    herein) of less than 100 nM, preferably less than 50 nM, more    preferably less than 20 nM, even more preferably less than 10 nM,    most preferred less than 1 nM. Such an amino acid sequence may in    particular be an amino acid sequence according to any of the    preceding aspects.-   Aspect A-10: An amino acid sequence that can specifically bind to    OX40L and has an IC50 value in the T-cell activation assay using    human donors (e.g. as defined herein) that is less than the IC50 of    the benchmark Fab (as defined herein, example section), or that is    preferably less than the benchmark IgG (as defined herein, SEQ ID    NO: 177 and 178). Such an amino acid sequence may in particular be    an amino acid sequence according to any of the preceding aspects.-   Aspect A-11: An amino acid sequence according to any of the    preceding aspects, that essentially consists of 4 framework regions    (FR1 to FR4 respectively) and 3 complementarity determining regions    (CDR1 to CDR3 respectively).-   Aspect A-12: An amino acid sequence according to any of the    preceding aspects that is a naturally occurring immunoglobulin    sequence (from any suitable species) or a synthetic or    semi-synthetic immunoglobulin sequence.-   Aspect A-13: An amino acid sequence according to any of the    preceding aspects that is a humanized immunoglobulin sequence, a    camelized immunoglobulin sequence or an immunoglobulin sequence that    has been obtained by techniques such as affinity maturation.-   Aspect A-14: An amino acid sequence according to any of the    preceding aspects, that essentially consists of an immunoglobulin    single variable domain sequence such as a light chain variable    domain sequence (e.g. a VL-sequence); or of a heavy chain variable    domain sequence (e.g. a VH-sequence).-   Aspect A-15: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a heavy chain    variable domain sequence that is derived from a conventional    four-chain antibody or that essentially consist of a heavy chain    variable domain sequence that is derived from heavy chain antibody.-   Aspect A-16: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a domain antibody    (or an amino acid sequence that is suitable for use as a domain    antibody), of a single domain antibody (or an amino acid sequence    that is suitable for use as a single domain antibody), of a “dAb”    (or an amino acid sequence that is suitable for use as a dAb) or of    a Nanobody (including but not limited to a VHH sequence).-   Aspect A-17: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a Nanobody.-   Aspect A-18: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 1 to 22, in which for the        purposes of determining the degree of amino acid identity, the        amino acid residues that form the CDR sequences are disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect A-19: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a polypeptide that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 186 to 198 and 227 to 234,        in which for the purposes of determining the degree of amino        acid identity, the amino acid residues that form the CDR        sequences are disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect A-20: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 179 to 185, in which for        the purposes of determining the degree of amino acid identity,        the amino acid residues that form the CDR sequences are        disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect A-21: An amino acid sequence according to any of the    preceding aspects, that essentially consists of a humanized    Nanobody.-   Aspect A-22: An amino acid sequence according to any of the    preceding aspects, that in addition to the at least one binding site    for binding against OX40L, contains one or more further binding    sites for binding against other antigens, proteins or targets.-   Aspect B-1: An amino acid sequence that is directed against and/or    that can specifically bind OX40L, and that comprises one or more    stretches of amino acid residues chosen from the group consisting    of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167;    -   or any suitable combination thereof.        Such an amino acid sequence may in particular be an amino acid        sequence according to any of the aspects A-1 to A-22.-   Aspect B-2: An amino acid sequence according to aspect B-1, in which    at least one of said stretches of amino acid residues forms part of    the antigen binding site for binding against OX40L.-   Aspect B-3: An amino acid sequence that is directed against and/or    that can specifically bind OX40L and that comprises two or more    stretches of amino acid residues chosen from the group consisting    of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167;    -   such that (i) when the first stretch of amino acid residues        corresponds to one of the amino acid sequences according to        a), b) or c), the second stretch of amino acid residues        corresponds to one of the amino acid sequences according to d),        e), f), g), h) or i); (ii) when the first stretch of amino acid        residues corresponds to one of the amino acid sequences        according to d), e) or f), the second stretch of amino acid        residues corresponds to one of the amino acid sequences        according to a), b), c), g), h) or i); or (iii) when the first        stretch of amino acid residues corresponds to one of the amino        acid sequences according to g), h) or i), the second stretch of        amino acid residues corresponds to one of the amino acid        sequences according to a), b), c), d), e) or f).        Such an amino acid sequence may in particular be an amino acid        sequence according to any of the aspects A-1 to A-22, B-1 and/or        B-2.-   Aspect B-4: An amino acid sequence according to aspect B-3, in which    the at least two stretches of amino acid residues forms part of the    antigen binding site for binding against OX40L.-   Aspect B-5: An amino acid sequence that is directed against and/or    that can specifically bind OX40L and that comprises three or more    stretches of amino acid residues, in which the first stretch of    amino acid residues is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   the second stretch of amino acid residues is chosen from the        group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and the third stretch of amino acid residues is chosen from the        group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.        Such an amino acid sequence may in particular be an amino acid        sequence according to any of the aspects A-1 to A-22 and/or B-1        to B-4.-   Aspect B-6: An amino acid sequence according to aspect B-5, in which    the at least three stretches of amino acid residues forms part of    the antigen binding site for binding against OX40L.-   Aspect B-7: An amino acid sequence that is directed against and/or    that can specifically bind OX40L in which the CDR sequences of said    amino acid sequence have at least 70% amino acid identity,    preferably at least 80% amino acid identity, more preferably at    least 90% amino acid identity, such as 95% amino acid identity or    more or even essentially 100% amino acid identity with the CDR    sequences of at least one of the amino acid sequences of SEQ ID    NO's: 179 to 185. Such an amino acid sequence may in particular be    an amino acid sequence according to any of the aspects A-1 to A-22    and/or B-1 to B-6.-   Aspect C-1: An amino acid sequence that is directed against OX40L    and that cross-blocks the binding of at least one of the amino acid    sequences of SEQ ID NO's: 179 to 185 to OX40L. Such an amino acid    sequence may in particular be an amino acid sequence according to    any of the aspects A-1 to A-22 and/or according to aspects B-1 to    B-7. Also, preferably, such an amino acid sequence is able to    specifically bind to OX40L.-   Aspect C-2: An amino acid sequence that is directed against OX40L    and that is cross-blocked from binding to OX40L by at least one of    the amino acid sequences of SEQ ID NO's: 179 to 185. Such an amino    acid sequence may in particular be an amino acid sequence according    to any of the aspects A-1 to A-22 and/or according to aspects B-1 to    B-7. Also, preferably, such an amino acid sequence is able to    specifically bind to OX40L.-   Aspect C-3: An amino acid sequence according to any of aspects C-1    or C-2, wherein the ability of said amino acid sequence to    cross-block or to be cross-blocked is detected in a Biacore assay.-   Aspect C-4: An amino acid sequence according to any of aspects C-1    to C-3 wherein the ability of said amino acid sequence to    cross-block or to be cross-blocked is detected in an ELISA assay.-   Aspect D-1: An amino acid sequence according to any of aspects B-1    to B-7 or C-1 to C-4, that is in essentially isolated form.-   Aspect D-2: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, and/or D1 for administration to a subject,    wherein said amino acid sequence does not naturally occur in said    subject.-   Aspect D-3: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, and/or D1 to D-2 that can specifically bind to    OX40L with a dissociation constant (K_(D)) of 10⁻⁵ to 10⁻¹²    moles/litre or less, and preferably 10⁻⁷ to 10⁻¹² moles/litre or    less and more preferably 10⁻⁸ to 10⁻² moles/litre.-   Aspect D-4: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, and/or D-1 to D-3 that can specifically bind to    OX40L with a rate of association (k_(on)-rate) of between 10² M⁻¹s⁻¹    to about 10⁷ M⁻¹s⁻¹, preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹,    more preferably between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between    10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹.-   Aspect D-5: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, and/or D-1 to D-4 that can specifically bind to    OX40L with a rate of dissociation (k_(off) rate) between 1 s⁻¹ and    10⁻⁶ s⁻¹ preferably between 10⁻² s⁻¹ and 10⁻⁶ s⁻¹, more preferably    between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as between 10⁻⁴ s⁻¹ and 10⁻⁶    s⁻¹.-   Aspect D-6: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, and/or D-1 to D-5 that can specifically bind to    OX40L with an affinity less than 500 nM, preferably less than 200    nM, more preferably less than 10 nM, such as less than 500 pM.    The amino acid sequences according to aspects D-1 to D-6 may in    particular be an amino acid sequence according to any of the aspects    A-1 to A-22.-   Aspect E-1: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4 and/or D-1 to D-6, that is a naturally occurring    amino acid sequence (from any suitable species) or a synthetic or    semi-synthetic amino acid sequence.-   Aspect E-2: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 that comprises an    immunoglobulin fold or that under suitable conditions is capable of    forming an immunoglobulin fold.-   Aspect E-3: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-2, that is an    immunoglobulin sequence.-   Aspect E-4: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-3, that is a    naturally occurring immunoglobulin sequence (from any suitable    species) or a synthetic or semi-synthetic immunoglobulin sequence.-   Aspect E-5: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-4 that is a    humanized immunoglobulin sequence, a camelized immunoglobulin    sequence or an immunoglobulin sequence that has been obtained by    techniques such as affinity maturation.-   Aspect E-6: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-5 that essentially    consists of an immunoglobulin single variable domain sequence such    as a light chain variable domain sequence (e.g. a V_(L)-sequence);    or of a heavy chain variable domain sequence (e.g. a    V_(H)-sequence).-   Aspect E-7: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-6, that essentially    consists of a heavy chain variable domain sequence that is derived    from a conventional four-chain antibody or that essentially consist    of a heavy chain variable domain sequence that is derived from heavy    chain antibody.-   Aspect E-8: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-7, that essentially    consists of a domain antibody (or an amino acid sequence that is    suitable for use as a domain antibody), of a single domain antibody    (or an amino acid sequence that is suitable for use as a single    domain antibody), of a “dAb” (or an amino acid sequence that is    suitable for use as a dAb) or of a Nanobody (including but not    limited to a V_(HH) sequence).-   Aspect E-9: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-8 that essentially    consists of a Nanobody.-   Aspect E-10: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-9 that essentially    consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 1 to 22, in which for the        purposes of determining the degree of amino acid identity, the        amino acid residues that form the CDR sequences are disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect E-11: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-10, that essentially    consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        An amino acid sequences of SEQ ID NO's: 179 to 185, in which for        the purposes of determining the degree of amino acid identity,        the amino acid residues that form the CDR sequences are        disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect E-12: An amino acid sequence according to any of aspects B-1    to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-11, that essentially    consists of a humanized Nanobody.-   Aspect E-13: An amino acid sequence according to any of the aspects    B-1 to B-7, C-1 to C-4, D-1 to D-6, and/or E-1 to E-12, that in    addition to the at least one binding site for binding formed by the    CDR sequences, contains one or more further binding sites for    binding against other antigens, proteins or targets.    The amino acid sequences according to aspects E-1 to E-13 may in    particular be an amino acid sequence according to any of the aspects    A-1 to A-22.-   Aspect F-1: An amino acid sequence that essentially consists of 4    framework regions (FR1 to FR4, respectively) and 3 complementarity    determining regions (CDR1 to CDR3, respectively), in which:    -   CDR1 is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   and/or    -   CDR2 is chosen from the group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and/or    -   CDR3 is chosen from the group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.        Such an amino acid sequence is preferably directed against OX40L        and/or an amino acid sequence that can specifically bind to        OX40L. Also, such an amino acid sequence is preferably an amino        acid sequence according to any of the aspects A-1 to A-22, C-1        to C-4, D1 to D-6 and/or E-1 to E-13.-   Aspect F-2: An amino acid sequence that essentially consists of 4    framework regions (FR1 to FR4, respectively) and 3 complementarity    determining regions (CDR1 to CDR3, respectively), in which:    -   CDR1 is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   and    -   CDR2 is chosen from the group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and    -   CDR3 is chosen from the group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.        Such an amino acid sequence is preferably directed against OX40L        and/or an amino acid sequence that can specifically bind to        OX40L. Also, such an amino acid sequence is preferably an amino        acid sequence according to any of the aspects A-1 to A-22, C-1        to C-4, D-1 to D-6 and/or E-1 to E-13.-   Aspect F-3: An amino acid sequence according to any of aspects F-1    and F-2, in which the CDR sequences of said amino acid sequence have    at least 70% amino acid identity, preferably at least 80% amino acid    identity, more preferably at least 90% amino acid identity, such as    95% amino acid identity or more or even essentially 100% amino acid    identity with the CDR sequences of at least one of the amino acid    sequences of SEQ ID NO's: 179 to 185.    Such an amino acid sequence is preferably directed against OX40L    and/or an amino acid sequence that can specifically bind to OX40L.    Also, such an amino acid sequence is preferably an amino acid    sequence according to any of the aspects A-1 to A-22, C-1 to C-4,    D-1 to D-6 and/or E-1 to E-13.-   Aspect F-4: An amino acid sequence according to any of aspects F-1    to F-3 that is directed against OX40L and that cross-blocks the    binding to OX40L of at least one of the amino acid sequences of SEQ    ID NO's: 179 to 185.-   Aspect F-5: An amino acid sequence according to any of aspects F-1    to F-3 that is directed against OX40L and that is cross-blocked from    binding to OX40L by at least one of the amino acid sequences of SEQ    ID NO's: 179 to 185.-   Aspect F-6: Amino acid sequence according to any of aspects F-4 or    F-5 wherein the ability of said amino acid sequence to cross-block    or to be cross-blocked is detected in a Biacore assay.-   Aspect F-7: Amino acid sequence according to any of aspects F4 or    F-5 wherein the ability of said amino acid sequence to cross-block    or to be cross-blocked is detected in an ELISA assay.-   Aspect F-8: An amino acid sequence according to any of aspects F-1    to F-7, that is in essentially isolated form.-   Aspect F-9: An amino acid sequence according to any of aspects F-1    to F-8, for administration to a subject, wherein said an amino acid    sequence does not naturally occur in said subject.-   Aspect F-10: An amino acid sequence according to any of aspects F-1    to F-9, that can specifically bind to OX40L with a dissociation    constant (K_(D)) of 10⁻⁵ to 10⁻¹² moles/litre or less, and    preferably 10⁻⁷ to 10⁻¹² moles/litre or less and more preferably    10⁻⁸ to 10⁻¹² moles/litre.-   Aspect F-11: An amino acid sequence according to any of aspects F-1    to F-10, that can specifically bind to OX40L with a rate of    association (k_(on)-rate) of between 10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹,    preferably between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more preferably    between 10⁴ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and    10⁷ M⁻¹s⁻¹.-   Aspect F-12: An amino acid sequence according to any of aspects F-1    to F-11, that can specifically bind to OX40L with a rate of    dissociation (k_(off) rate) between 1 s⁻¹ and 10⁻⁶ s⁻¹ preferably    between 10⁻² s⁻¹ and 10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and    10⁻⁶ s⁻¹, such as between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.-   Aspect F-13: An amino acid sequence according to any of aspects F-1    to F-12, that can specifically bind to OX40L with an affinity less    than 500 nM, preferably less than 200 nM, more preferably less than    10 nM, such as less than 500 pM.-   Aspect F-14: An amino acid sequence according to any of aspects F-1    to F-13, that is a naturally occurring amino acid sequence (from any    suitable species) or a synthetic or semi-synthetic amino acid    sequence.-   Aspect F-15: An amino acid sequence according to any of aspects F-1    to F-14, that comprises an immunoglobulin fold or that under    suitable conditions is capable of forming an immunoglobulin fold.-   Aspect F-16: An amino acid sequence according to any of aspects F-1    to F-15, that is an immunoglobulin sequence.-   Aspect F-17: An amino acid sequence according to any of aspects F-1    to F-16, that is a naturally occurring immunoglobulin sequence (from    any suitable species) or a synthetic or semi-synthetic    immunoglobulin sequence.-   Aspect F-18: An amino acid sequence according to any of aspects F-1    to F-17, that is a humanized immunoglobulin sequence, a camelized    immunoglobulin sequence or an immunoglobulin sequence that has been    obtained by techniques such as affinity maturation.-   Aspect F-19: An amino acid sequence according to any of aspects F-1    to F-18, that essentially consists of an immunoglobulin single    variable domain sequence such as a light chain variable domain    sequence (e.g. a V_(H)-sequence); or of a heavy chain variable    domain sequence (e.g. a V_(H)-sequence).-   Aspect F-20: An amino acid sequence according to any of aspects F-1    to F-19, that essentially consists of a heavy chain variable domain    sequence that is derived from a conventional four-chain antibody or    that essentially consist of a heavy chain variable domain sequence    that is derived from heavy chain antibody.-   Aspect F-21: An amino acid sequence according to any of aspects F-1    to F-20, that essentially consists of a domain antibody (or an amino    acid sequence that is suitable for use as a domain antibody), of a    single domain antibody (or an amino acid sequence that is suitable    for use as a single domain antibody), of a “dAb” (or an amino acid    sequence that is suitable for use as a dAb) or of a Nanobody    (including but not limited to a V_(HH) sequence).-   Aspect F-22: An amino acid sequence according to any of aspects F-1    to F-21, that essentially consists of a Nanobody.-   Aspect F-23: An amino acid sequence according to any of aspects F-1    to F-22, that essentially consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 1 to 22, in which for the        purposes of determining the degree of amino acid identity, the        amino acid residues that form the CDR sequences are disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect F-24: An amino acid sequence according to any of aspects F-1    to F-23, that essentially consists of a Nanobody that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 179 to 185, in which for        the purposes of determining the degree of amino acid identity,        the amino acid residues that form the CDR sequences are        disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect F-25: An amino acid sequence according to any of aspects F-1    to F-24, that essentially consists of a humanized Nanobody.-   Aspect G-1: An amino acid sequence according to any of the preceding    aspects, that in addition to the at least one binding site for    binding formed by the CDR sequences, contains one or more further    binding sites for binding against another antigen, protein or    target.-   Aspect H-1: Nanobody that is directed against and/or that can    specifically bind to OX40L. Aspect H-2: Nanobody according to aspect    H-1, that is in essentially isolated form.-   Aspect H-3: Nanobody according to any of aspects H-1 to H-2, that    can specifically bind to OX40L with a dissociation constant (K_(D))    of 10⁻⁵ to 10⁻¹² moles/litre or less, and preferably 10⁻⁷ to 10⁻²    moles/litre or less and more preferably 10⁻⁸ to 10⁻² moles/litre.-   Aspect H-4: Nanobody according to any of aspects H-1 to H-3, that    can specifically bind to OX40L with a rate of association    (k_(on)-rate) of between 10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹, preferably    between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more preferably between 10⁴    M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹.-   Aspect H-5: Nanobody according to any of aspects H-1 to H-4, that    can specifically bind to OX40L with a rate of dissociation (k_(off)    rate) between 1 s⁻¹ and 10⁻⁶ s⁻¹ preferably between 10⁻² s⁻¹ and    10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as    between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.-   Aspect H-6: Nanobody according to any of aspects H-1 to H-5, that    can specifically bind to OX40L with an affinity less than 500 nM,    preferably less than 200 nM, more preferably less than 10 nM, such    as less than 500 pM.-   Aspect H-7: Nanobody that can specifically bind to OX40L and that    has an IC50 value in the alphascreen assay (e.g. as defined herein)    with 0.12 nM hOX40L and 0.2 nM OX40/Fc of less than 10 nM,    preferably less than 1 nM, more preferably less than 500 pM, even    more preferably less than 1 nM, most preferred less than 100 pM.    Such a Nanobody may in particular be an amino acid sequence and/or    Nanobody according to any of the preceding aspects.-   Aspect H-8: Nanobody that can specifically bind to OX40L and that    has an IC50 value in the FACS assay (e.g. as defined herein) of less    than 100 nM, preferably less than 50 nM, more preferably less than    20 nM, even more preferably less than 10 nM, most preferred less    than 1 nM. Such a Nanobody may in particular be a an amino acid    sequence and/or Nanobody according to any of the preceding aspects.-   Aspect H-9: Nanobody that can specifically bind to OX40L and that    has an IC50 value in the T-cell activation assay using human donors    (e.g. as defined herein) that is less than the IC50 of the benchmark    Fab (as defined herein, example section), or that is preferably less    than the benchmark IgG (as defined herein, SEQ ID NO: 177 and 178).    Such a Nanobody may in particular be an amino acid sequence and/or    Nanobody according to any of the preceding aspects.-   Aspect H-10: Nanobody according to any of aspects H-1 to H-9, that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 179 to 185, in which for        the purposes of determining the degree of amino acid identity,        the amino acid residues that form the CDR sequences are        disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   Aspect H-11: Nanobody according to any of aspects H-1 to H-10, in    which:    -   CDR1 is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   and/or    -   CDR2 is chosen from the group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and/or    -   CDR3 is chosen from the group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.-   Aspect H-12: Nanobody according to any of aspects H-1 to H-11, in    which:    -   CDR1 is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   and    -   CDR2 is chosen from the group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and    -   CDR3 is chosen from the group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.-   Aspect H-13: Nanobody according to any of aspects H-1 to H-12, in    which the CDR sequences have at least 70% amino acid identity,    preferably at least 80% amino acid identity, more preferably at    least 90% amino acid identity, such as 95% amino acid identity or    more or even essentially 100% amino acid identity with the CDR    sequences of at least one of the amino acid sequences of SEQ ID    NO's: 179 to 185.-   Aspect H-14: Nanobody according to any of aspects H-1 to H-13, which    is a partially humanized Nanobody.-   Aspect H-15: Nanobody according to any of aspects H-1 to H-14, which    is a fully humanized Nanobody.-   Aspect H-16: Nanobody according to any of aspects H-1 to H-15, that    is chosen from the group consisting of SEQ ID NO's: 179 to 185 or    from the group consisting of from amino acid sequences that have    more than 80%, preferably more than 90%, more preferably more than    95%, such as 99% or more sequence identity (as defined herein) with    at least one of the amino acid sequences of SEQ ID NO's: 179 to 185.-   Aspect H-17: Nanobody according to any of aspects H-1 to H-16, which    is a humanized Nanobody that is chosen from the group consisting of    SEQ ID NO's: 199 to 226 or from the group consisting of amino acid    sequences that have more than 80%, preferably more than 90%, more    preferably more than 95%, such as 99% or more sequence identity (as    defined herein) with at least one of the amino acid sequences of SEQ    ID NO's: 199 to 226.-   Aspect H-18: Nanobody according to any of aspects H-1 to H-17, that    is chosen from the group consisting of SEQ ID NO's: 179 to 185 or    from the group consisting of SEQ ID NO's: 199 to 226.-   Aspect H-19: Nanobody directed against OX40L that cross-blocks the    binding to OX40L of at least one of the amino acid sequences of SEQ    ID NO's: 179 to 185 and 199 to 226.-   Aspect H-20: Nanobody directed against OX40L that is cross-blocked    from binding to OX40L by at least one of the amino acid sequences of    SEQ ID NO's: 179 to 185 and 199 to 226.-   Aspect H-21: Nanobody according to any of aspects H-19 or H-20    wherein the ability of said Nanobody to cross-block or to be    cross-blocked is detected in a Biacore assay.-   Aspect H-22: Nanobody according to any of aspects H-19 to H-21    wherein the ability of said Nanobody to cross-block or to be    cross-blocked is detected in an ELISA assay.-   Aspect K-1: Polypeptide that comprises or essentially consists of    one or more amino acid sequences according to any of aspects A-1 to    A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25    or G-1 (of the invention) and/or one or more Nanobodies according to    any of aspects H-1 to H-22, and optionally further comprises one or    more other residues or binding units, optionally linked via one or    more peptidic linkers.-   Aspect K-2: Polypeptide according to aspect K-1, in which said one    or more binding units are immunoglobulin sequences.-   Aspect K-3: Polypeptide according to any of aspects K-1 or K-2, in    which said one or more other residues or binding units are chosen    from the group consisting of domain antibodies, amino acid sequences    that are suitable for use as a domain antibody, single domain    antibodies, amino acid sequences that are suitable for use as a    single domain antibody, “dAb”'s, amino acid sequences that are    suitable for use as a dAb, or Nanobodies.-   Aspect K-4: Polypeptide according to any of aspects K-1 to K-3, in    which said one or more amino acid sequences of the invention are    immunoglobulin sequences.-   Aspect K-5: Polypeptide according to any of aspects K-1 to K-4, in    which said one or more amino acid sequences of the invention are    chosen from the group consisting of domain antibodies, amino acid    sequences that are suitable for use as a domain antibody, single    domain antibodies, amino acid sequences that are suitable for use as    a single domain antibody, “dAb”'s, amino acid sequences that are    suitable for use as a dAb, or Nanobodies.-   Aspect K-6: Polypeptide according to any of aspects K-1 to K-5, that    comprises or essentially consists of one or more Nanobodies    according to any of aspects H-1 to H-22 and in which said one or    more other binding units are Nanobodies.-   Aspect K-7: Polypeptide according to any of aspects K-1 to K-6,    which is a multivalent construct.-   Aspect K-8: Polypeptide according to any of aspects K-1 to K-7,    which is a multispecific construct.-   Aspect K-9: Polypeptide according to any of aspects K-1 to K-8,    which is a multiparatopic construct.-   Aspect K-10: Polypeptide according to any of aspects K-1 to K-9,    which has an increased half-life, compared to the corresponding    amino acid sequence according to any of aspects A-1 to A-22, B-1 to    B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25 or G-1 per se    or Nanobody according to any of aspects H-1 to H-22 per se,    respectively.-   Aspect K-11: Polypeptide according to aspect K-10, in which said one    or more other binding units provide the polypeptide with increased    half-life, compared to the corresponding amino acid sequence    according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1    to D-6, E-1 to E-13, F-1 to F-25 or G-1 per se or Nanobody according    to any of aspects H-1 to H-22 per se, respectively.-   Aspect K-12: Polypeptide according to aspect K-10 or K-11, in which    said one or more other binding units that provide the polypeptide    with increased half-life is chosen from the group consisting of    serum proteins or fragments thereof, binding units that can bind to    serum proteins, an Fc portion, and small proteins or peptides that    can bind to serum proteins.-   Aspect K-13: Polypeptide according to any of aspects K-10 to K-12,    in which said one or more other binding units that provide the    polypeptide with increased half-life is chosen from the group    consisting of human serum albumin or fragments thereof.-   Aspect K-14: Polypeptide according to any of aspect K-10 to K-13, in    which said one or more other binding units that provides the    polypeptide with increased half-life are chosen from the group    consisting of binding units that can bind to serum albumin (such as    human serum albumin) or a serum immunoglobulin (such as IgG).-   Aspect K-15: Polypeptide according to any of aspects K-10 to K-14,    in which said one or more other binding units that provides the    polypeptide with increased half-life are chosen from the group    consisting of domain antibodies, amino acid sequences that are    suitable for use as a domain antibody, single domain antibodies,    amino acid sequences that are suitable for use as a single domain    antibody, “dAb”'s, amino acid sequences that are suitable for use as    a dAb, or Nanobodies that can bind to serum albumin (such as human    serum albumin) or a serum immunoglobulin (such as IgG).-   Aspect K-16: Polypeptide according to aspect K-10 to K-15, in which    said one or more other binding units that provides the polypeptide    with increased half-life is a Nanobody that can bind to serum    albumin (such as human serum albumin) or a serum immunoglobulin    (such as IgG).-   Aspect K-17: Polypeptide according to any of aspects K-10 to K-16,    that has a serum half-life that is at least 1.5 times, preferably at    least 2 times, such as at least 5 times, for example at least 10    times or more than 20 times, greater than the half-life of the    corresponding amino acid sequence according to any of aspects A-1 to    A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25    or G-1 per se or Nanobody according to any of aspects H-1 to H-22    per se, respectively.-   Aspect K-18: Polypeptide according to any of aspects K-10 to K-17,    that has a serum half-life that is increased with more than 1 hours,    preferably more than 2 hours, more preferably more than 6 hours,    such as more than 12 hours, or even more than 24, 48 or 72 hours,    compared to the corresponding amino acid sequence according to any    of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1 per se or Nanobody according to any of    aspects H-1 to H-22 per se, respectively.-   Aspect K-19: Polypeptide according to any of aspects K-1 to K-18,    that has a serum half-life in human of at least about 12 hours,    preferably at least 24 hours, more preferably at least 48 hours,    even more preferably at least 72 hours or more; for example, of at    least 5 days (such as about 5 to 10 days), preferably at least 9    days (such as about 9 to 14 days), more preferably at least about 10    days (such as about 10 to 15 days), or at least about 11 days (such    as about 11 to 16 days), more preferably at least about 12 days    (such as about 12 to 18 days or more), or more than 14 days (such as    about 14 to 19 days).-   Aspect K-20: Polypeptide according to aspect K-10 or K-11, that is    chosen from the group consisting of SEQ ID NO's: 186 to 198 and 227    to 234 or from the group consisting of from amino acid sequences    that have more than 80%, preferably more than 90%, more preferably    more than 95%, such as 99% or more sequence identity (as defined    herein) with at least one of the amino acid sequences of SEQ ID    NO's: 186 to 198 and 227 to 234.-   Aspect K-21: Polypeptide according to aspect K-10 or K-11, that is    chosen from the group consisting of SEQ ID NO's: 186 to 198 and 227    to 234, more preferably one of SEQ ID NO's: 190, 227, 228, 231 and    233.-   Aspect L-1: Compound or construct, that comprises or essentially    consists of one or more amino acid sequences according to any of    aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1 and/or one or more Nanobodies according to    any of aspects H-1 to H-22, and optionally further comprises one or    more other groups, residues, moieties or binding units, optionally    linked via one or more linkers.-   Aspect L-2: Compound or construct according to aspect L-1, in which    said one or more other groups, residues, moieties or binding units    are amino acid sequences.-   Aspect L-3: Compound or construct according to aspect L-1 or L-2, in    which said one or more linkers, if present, are one or more amino    acid sequences.-   Aspect L-4: Compound or construct according to any of aspects L-1 to    L-3, in which said one or more other groups, residues, moieties or    binding units are immunoglobulin sequences.-   Aspect L-5: Compound or construct according to any of aspects L-1 to    L-4, in which said one or more other groups, residues, moieties or    binding units are chosen from the group consisting of domain    antibodies, amino acid sequences that are suitable for use as a    domain antibody, single domain antibodies, amino acid sequences that    are suitable for use as a single domain antibody, “dAb”'s, amino    acid sequences that are suitable for use as a dAb, or Nanobodies.-   Aspect L-6: Compound or construct according to any of aspects L-1 to    L-5, in which said one or more amino acid sequences of the invention    are immunoglobulin sequences.-   Aspect L-7: Compound or construct according to any of aspects L-1 to    L-6, in which said one or more amino acid sequences of the invention    are chosen from the group consisting of domain antibodies, amino    acid sequences that are suitable for use as a domain antibody,    single domain antibodies, amino acid sequences that are suitable for    use as a single domain antibody, “dAb”'s, amino acid sequences that    are suitable for use as a dAb, or Nanobodies.-   Aspect L-8: Compound or construct according to any of aspects L-1 to    L-7, that comprises or essentially consists of one or more    Nanobodies according to any of aspects H-1 to H-22 and in which said    one or more other groups, residues, moieties or binding units are    Nanobodies.-   Aspect L-9: Compound or construct according to any of aspects L-1 to    L-8, which is a multivalent construct.-   Aspect L-10: Compound or construct according to any of aspects L-1    to L-9, which is a multispecific construct.-   Aspect L-11: Compound or construct according to any of aspects L-1    to L-10, which has an increased half-life, compared to the    corresponding amino acid sequence according to any of aspects A-1 to    A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25    or G-1 per se or Nanobody according to any of aspects H-1 to H-22    per se, respectively.-   Aspect L-12: Compound or construct according to aspect L-1 to L-11,    in which said one or more other groups, residues, moieties or    binding units provide the compound or construct with increased    half-life, compared to the corresponding amino acid sequence    according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1    to D-6, E-1 to E-13, F-1 to F-25 or G-1 per se or Nanobody according    to any of aspects H-1 to H-22 per se, respectively.-   Aspect L-13: Compound or construct according to aspect L-12, in    which said one or more other groups, residues, moieties or binding    units that provide the compound or construct with increased    half-life is chosen from the group consisting of serum proteins or    fragments thereof, binding units that can bind to serum proteins, an    Fc portion, and small proteins or peptides that can bind to serum    proteins.-   Aspect L-14: Compound or construct according to aspect L-12 or L-13,    in which said one or more other groups, residues, moieties or    binding units that provide the compound or construct with increased    half-life is chosen from the group consisting of human serum albumin    or fragments thereof.-   Aspect L-15: Compound or construct according to any of aspects L-12    to L-14, in which said one or more other groups, residues, moieties    or binding units that provides the compound or construct with    increased half-life are chosen from the group consisting of binding    units that can bind to serum albumin (such as human serum albumin)    or a serum immunoglobulin (such as IgG).-   Aspect L-16: Compound or construct according to any of aspects L-12    to L-15, in which said one or more other groups, residues, moieties    or binding units that provides the compound or construct with    increased half-life are chosen from the group consisting of domain    antibodies, amino acid sequences that are suitable for use as a    domain antibody, single domain antibodies, amino acid sequences that    are suitable for use as a single domain antibody, “dAb”'s, amino    acid sequences that are suitable for use as a dAb, or Nanobodies    that can bind to serum albumin (such as human serum albumin) or a    serum immunoglobulin (such as IgG).-   Aspect L-17: Compound or construct according to any of aspects L-12    to L-16, in which said one or more other groups, residues, moieties    or binding units that provides the compound or construct with    increased half-life is a Nanobody that can bind to serum albumin    (such as human serum albumin) or a serum immunoglobulin (such as    IgG).-   Aspect L-18: Compound or construct according to any of aspects L-12    to L-17, that has a serum half-life that is at least 1.5 times,    preferably at least 2 times, such as at least 5 times, for example    at least 10 times or more than 20 times, greater than the half-life    of the corresponding amino acid sequence according to any of aspects    A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to    F-25 or G-1 per se or Nanobody according to any of aspects H-1 to    H-22 per se, respectively.-   Aspect L-19: Compound or construct according to any of aspects L-12    to L-18, that has a serum half-life that is increased with more than    1 hours, preferably more than 2 hours, more preferably more than 6    hours, such as more than 12 hours, or even more than 24, 48 or 72    hours, compared to the corresponding amino acid sequence according    to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6,    E-1 to E-13, F-1 to F-25 or G-1 per se or Nanobody according to any    of aspects H-1 to H-22 per se, respectively.-   Aspect L-20: Compound or construct according to any of aspects L-12    to L-19, that has a serum half-life in human of at least about 12    hours, preferably at least 24 hours, more preferably at least 48    hours, even more preferably at least 72 hours or more; for example,    of at least 5 days (such as about 5 to 10 days), preferably at least    9 days (such as about 9 to 14 days), more preferably at least about    10 days (such as about 10 to 15 days), or at least about 11 days    (such as about 11 to 16 days), more preferably at least about 12    days (such as about 12 to 18 days or more), or more than 14 days    (such as about 14 to 19 days).-   Aspect L-21: Monovalent construct, comprising or essentially    consisting of one amino acid sequence according to any of aspects    A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to    F-25 or G-1 and/or one Nanobody according to any of aspects H-1 to    H-22.-   Aspect L-22: Monovalent construct according to aspect L-21, in which    said amino acid sequence of the invention is chosen from the group    consisting of domain antibodies, amino acid sequences that are    suitable for use as a domain antibody, single domain antibodies,    amino acid sequences that are suitable for use as a single domain    antibody, “dAb”'s, amino acid sequences that are suitable for use as    a dAb, or Nanobodies.-   Aspect L-23: Monovalent construct, comprising or essentially    consisting of one Nanobody according to any of aspects H-1 to H-22.-   Aspect M-1: Nucleic acid or nucleotide sequence, that encodes an    amino acid sequence according to any of aspects A-1 to A-22, B-1 to    B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25 or G-1, a    Nanobody according to any of aspects H-1 to H-22, a polypeptide    according to any of aspects K-1 to K-21, a compound or construct    according to any of aspects L-1 to L-20 that is such that it can be    obtained by expression of a nucleic acid or nucleotide sequence    encoding the same, or a monovalent construct according to any of    aspects L-21 to L-23.-   Aspect M-2: Nucleic acid or nucleotide sequence according to aspect    M-1, that is in the form of a genetic construct.-   Aspect N-1: Host or host cell that expresses, or that under suitable    circumstances is capable of expressing, an amino acid sequence    according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1    to D-6, E-1 to E-13, F-1 to F-25 or G-1, a Nanobody according to any    of aspects H-1 to H-22, a polypeptide according to any of aspects    K-1 to K-21, a compound or construct according to any of aspects L-1    to L-20 that is such that it can be obtained by expression of a    nucleic acid or nucleotide sequence encoding the same, or a    monovalent construct according to any of aspects L-21 to L-23;    and/or that comprises a nucleic acid or nucleotide sequence    according to aspect M-1 or a genetic construct according to aspect    M-2.-   Aspect 0-1: Composition comprising at least one amino acid sequence    according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1    to D-6, E-1 to E-13, F-1 to F-25 or G-1, Nanobody according to any    of aspects H-1 to H-22, polypeptide according to any of aspects K-1    to K-21, compound or construct according to any of aspects L-1 to    L-20, monovalent construct according to any of aspects L-21 to L-23,    or nucleic acid or nucleotide sequence according to aspects M-1 or    M-2.-   Aspect 0-2: Composition according to aspect 0-1, which is a    pharmaceutical composition.-   Aspect 0-3: Composition according to aspect 0-2, which is a    pharmaceutical composition, that further comprises at least one    pharmaceutically acceptable carrier, diluent or excipient and/or    adjuvant, and that optionally comprises one or more further    pharmaceutically active polypeptides and/or compounds.-   Aspect P-1: Method for producing an amino acid sequence according to    any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1    to E-13, F-1 to F-25 or G-1, a Nanobody according to any of aspects    H-1 to H-22, a polypeptide according to any of aspects K-1 to K-21,    a compound or construct according to any of aspects L-1 to L-20 that    is such that it can be obtained by expression of a nucleic acid or    nucleotide sequence encoding the same, or a monovalent construct    according to any of aspects L-21 to L-23, said method at least    comprising the steps of:    -   a) expressing, in a suitable host cell or host organism or in        another suitable expression system, a nucleic acid or nucleotide        sequence according to aspect M-1, or a genetic construct        according to aspect M-2;    -   optionally followed by:    -   b) isolating and/or purifying the amino acid sequence according        to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to        D-6, E-1 to E-13, F-1 to F-25 or G-1, the Nanobody according to        any of aspects H-1 to H-22, the polypeptide according to any of        aspects K-1 to K-21, the compound or construct according to any        of aspects L-1 to L-20, or the monovalent construct according to        any of aspects L-21 to L-23 thus obtained.-   Aspect P-2: Method for producing an amino acid sequence according to    any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1    to E-13, F-1 to F-25 or G-1, a Nanobody according to any of aspects    H-1 to H-22, a polypeptide according to any of aspects K-1 to K-21,    a compound or construct according to any of aspects L-1 to L-20 that    is such that it can be obtained by expression of a nucleic acid or    nucleotide sequence encoding the same, or a monovalent construct    according to any of aspects L-21 to L-23, said method at least    comprising the steps of:    -   a) cultivating and/or maintaining a host or host cell according        to aspect N-1 under conditions that are such that said host or        host cell expresses and/or produces at least one amino acid        sequence according to any of aspects A-1 to A-22, B-1 to B-7,        C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25 or G-1,        Nanobody according to any of aspects H-1 to H-22, polypeptide        according to any of aspects K-1 to K-21, compound or construct        according to any of aspects L-1 to L-20, or monovalent construct        according to any of aspects L-21 to L-23;    -   optionally followed by:    -   b) isolating and/or purifying the amino acid sequence according        to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to        D-6, E-1 to E-13, F-1 to F-25 or G-1, Nanobody according to any        of aspects H-1 to H-22, polypeptide according to any of aspects        K-1 to K-21, compound or construct according to any of aspects        L-1 to L-20, or monovalent construct according to any of aspects        L-21 to L-23 thus obtained.-   Aspect Q-1: Method for screening amino acid sequences directed    against OX40L that comprises at least the steps of:    -   a) providing a set, collection or library of nucleic acid        sequences encoding amino acid sequences;    -   b) screening said set, collection or library of nucleic acid        sequences for nucleic acid sequences that encode an amino acid        sequence that can bind to and/or has affinity for OX40L and that        is cross-blocked or is cross blocking a Nanobody of the        invention, e.g. one of SEQ ID NO: 179 to 185 (Table-1), or a        humanized Nanobody of the invention, e.g. one of SEQ ID NO's:        199 to 226, or a polypeptide or construct of the invention, e.g.        one of SEQ ID NO: 186 to 198 (see Table A-3) and 227 to 234        (Table A-4); and    -   c) isolating said nucleic acid sequence, followed by expressing        said amino acid sequence.-   Aspect R-1: Method for the prevention and/or treatment of at least    one inflammatory disease and/or disorder such as e.g. asthma,    allergic asthma, chronic colitis, Crohn's disease, inflammatory    bowel disease, and/or atherosclerosis said method comprising    administering, to a subject in need thereof, a pharmaceutically    active amount of at least one amino acid sequence according to any    of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1, Nanobody according to any of aspects H-1    to H-22, polypeptide according to any of aspects K-1 to K-21,    compound or construct according to any of aspects L-1 to L-20,    monovalent construct according to any of aspects L-21 to L-23; or    composition according to aspect 0-2 or 0-3.-   Aspect R-2: Method for the prevention and/or treatment of at least    one disease or disorder that is associated with OX40L, with its    biological or pharmacological activity, and/or with the biological    pathways or signalling in which OX40L is involved, said method    comprising administering, to a subject in need thereof, a    pharmaceutically active amount of at least one amino acid sequence    according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1    to D-6, E-1 to E-13, F-1 to F-25 or G-1, Nanobody according to any    of aspects H-1 to H-22, polypeptide according to any of aspects K-1    to K-21, compound or construct according to any of aspects L-1 to    L-20, monovalent construct according to any of aspects L-21 to L-23;    or composition according to aspect 0-2 or 0-3.-   Aspect R-3: Method for the prevention and/or treatment of at least    one disease or disorder that can be prevented and/or treated by    administering, to a subject in need thereof, at least one amino acid    sequence according to any of aspects A-1 to A-22, B-1 to B-7, C-1 to    C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25 or G-1, Nanobody according    to any of aspects H-1 to H-22, polypeptide according to any of    aspects K-1 to K-21, compound or construct according to any of    aspects L-1 to L-20, monovalent construct according to any of    aspects L-21 to L-23; or composition according to aspect 0-2 or 0-3,    said method comprising administering, to a subject in need thereof,    a pharmaceutically active amount of at least one at least one amino    acid sequence according to any of aspects A-1 to A-22, B-1 to B-7,    C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25 or G-1, Nanobody    according to any of aspects H-1 to H-22, polypeptide according to    any of aspects K-1 to K-21, compound or construct according to any    of aspects L-1 to L-20, monovalent construct according to any of    aspects L-21 to L-23; or composition according to aspect 0-2 or 0-3.-   Aspect R-4: Method for immunotherapy, said method comprising    administering, to a subject in need thereof, a pharmaceutically    active amount of at least one amino acid sequence according to any    of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1, Nanobody according to any of aspects H-1    to H-22, polypeptide according to any of aspects K-1 to K-21,    compound or construct according to any of aspects L-1 to L-20,    monovalent construct according to any of aspects L-21 to L-23; or    composition according to aspect 0-2 or 0-3.-   Aspect R-5: Use of an amino acid sequence according to any of    aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1, a Nanobody according to any of aspects H-1    to H-22, a polypeptide according to any of aspects K-1 to K-21, a    compound or construct according to any of aspects L-1 to L-20, or a    monovalent construct according to any of aspects L-21 to L-23 in the    preparation of a pharmaceutical composition for prevention and/or    treatment of at least one inflammatory disease and/or disorder such    as e.g. asthma, allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or arthrosclerosis; and/or for use    in one or more of the methods according to aspects R-1 to R-4.-   Aspect R-6: Amino acid sequence according to any of aspects A-1 to    A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25    or G-1, Nanobody according to any of aspects H-1 to H-22,    polypeptide according to any of aspects K-1 to K-21, compound or    construct according to any of aspects L-1 to L-20, monovalent    construct according to any of aspects L-21 or L-23; or composition    according to aspect 0-2 or 0-3 for the prevention and/or treatment    of at least one inflammatory disease and/or disorders such as e.g.    asthma, allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or arthrosclerosis.-   Aspect S-1: Part or fragment of an amino acid sequence according to    any of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1    to E-13, F-1 to F-25 or G-1, or of a Nanobody according to any of    aspects H-1 to H-22.-   Aspect S-2: Part or fragment according to aspect S-1, that can    specifically bind to OX40L.-   Aspect S-3: Part of fragment according to any of aspects S-1 or S-2,    that can specifically bind to OX40L with a dissociation constant    (K_(D)) of 10⁻⁵ to 10⁻¹² moles/litre or less, and preferably 10⁻⁷ to    10⁻² moles/litre or less and more preferably 10⁻⁸ to 10⁻²    moles/litre.-   Aspect S-4: Part or fragment according to any of aspects S-1 to S-3,    that can specifically bind to OX40L with a rate of association    (k_(on)-rate) of between 10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹, preferably    between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more preferably between 10⁴    M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹.-   Aspect S-5: Part or fragment according to any of aspects S-1 to S-4,    that can specifically bind to OX40L with a rate of dissociation    (k_(off) rate) between 1 s⁻¹ and 10⁻⁶ s⁻¹ preferably between 10⁻²    s⁻¹ and 10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹,    such as between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.-   Aspect S-6: Compound or construct, that comprises or essentially    consists of one or more parts or fragments according to any of    aspects S-1 to S-4, and optionally further comprises one or more    other groups, residues, moieties or binding units, optionally linked    via one or more linkers.-   Aspect S-7: Compound or construct according to aspect S-6, in which    said one or more other groups, residues, moieties or binding units    are amino acid sequences.-   Aspect S-8: Compound or construct according to aspect S-6 or S-7, in    which said one or more linkers, if present, are one or more amino    acid sequences.-   Aspect S-9: Nucleic acid or nucleotide sequence, that encodes a part    or fragment according to any of aspects S-1 to S-5 or a compound or    construct according to any of aspect S-6 to S-8.-   Aspect S-10: Composition, comprising at least one part or fragment    according to any of aspects S-1 to S-5, compound or construct    according to any of aspects S-6 to S-8, or nucleic acid or    nucleotide sequence according to aspect S-9.-   Aspect T-1: Derivative of an amino acid sequence according to any of    aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1, or of a Nanobody according to any of    aspects H-1 to H-22.-   Aspect T-2: Derivative according to aspect T-1, that can    specifically bind to OX40L.-   Aspect T-3: Derivative according to any of aspects T-1 or T-2, that    can specifically bind to OX40L with a dissociation constant (K_(D))    of 10⁻⁵ to 10⁻¹² moles/litre or less, and preferably 10⁻⁷ to 10⁻¹²    moles/litre or less and more preferably 10⁻⁸ to 10⁻¹² moles/litre.-   Aspect T-4: Derivative according to any of aspects T-1 to T-3, that    can specifically bind to OX40L with a rate of association    (k_(on)-rate) of between 10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹, preferably    between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more preferably between 10⁴    M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹.-   Aspect T-5: Derivative according to any of aspects T-1 to T-4, that    can specifically bind to OX40L with a rate of dissociation (k_(off)    rate) between 1 s⁻¹ and 10⁻⁶ s⁻¹ preferably between 10⁻² s⁻¹ and    10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as    between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.-   Aspect T-6: Derivative of a polypeptide according to any of aspects    K-1 to K-21 or compound or construct according to any of aspects L-1    to L-23.-   Aspect T-7: Derivative according to aspect T-6, that can    specifically bind to OX40L.-   Aspect T-8: Derivative according to any of aspects T-6 or T-7, that    can specifically bind to OX40L with a dissociation constant (K_(D))    of 10⁻⁵ to 10⁻¹² moles/liter or less, and preferably 10⁻⁷ to 10⁻¹²    moles/liter or less and more preferably 10⁻⁸ to 10⁻¹² moles/liter.-   Aspect T-9: Derivative according to any of aspects T-6 to T-8, that    can specifically bind to OX40L with a rate of association    (k_(on)-rate) of between 10² M⁻¹s⁻¹ to about 10⁷ M⁻¹s⁻¹, preferably    between 10³ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, more preferably between 10⁴    M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹, such as between 10⁵ M⁻¹s⁻¹ and 10⁷ M⁻¹s⁻¹.-   Aspect T-10: Derivative according to any of aspects T-6 to T-9, that    can specifically bind to OX40L with a rate of dissociation (k_(off)    rate) between 1 s⁻¹ and 10⁻⁶ s⁻¹ preferably between 10⁻² s⁻¹ and    10⁻⁶ s⁻¹, more preferably between 10⁻³ s⁻¹ and 10⁻⁶ s⁻¹, such as    between 10⁻⁴ s⁻¹ and 10⁻⁶ s⁻¹.-   Aspect T-11: Derivative according to any of aspects T-1 to T-10,    that has a serum half-life that is at least 1.5 times, preferably at    least 2 times, such as at least 5 times, for example at least 10    times or more than 20 times, greater than the half-life of the    corresponding amino acid sequence according to any of aspects A-1 to    A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to E-13, F-1 to F-25    or G-1 per se, Nanobody according to any of aspects H-1 to H-22 per    se, polypeptide according to any of aspects K-1 to K-21 or compound    or construct according to any of aspects L-1 to L-23 per se.-   Aspect T-12: Derivative according to any of aspects T-1 to T-11,    that has a serum half-life that is increased with more than 1 hours,    preferably more than 2 hours, more preferably more than 6 hours,    such as more than 12 hours, or even more than 24, 48 or 72 hours,    compared to the corresponding amino acid sequence according to any    of aspects A-1 to A-22, B-1 to B-7, C-1 to C-4, D-1 to D-6, E-1 to    E-13, F-1 to F-25 or G-1 per se, Nanobody according to any of    aspects H-1 to H-23 per se, polypeptide according to any of aspects    K-1 to K-21 or compound or construct according to any of aspects L-1    to L-23 per se, respectively.-   Aspect T-13: Derivative according to any of aspects T-1 to T-12,    that has a serum half-life in human of at least about 12 hours,    preferably at least 24 hours, more preferably at least 48 hours,    even more preferably at least 72 hours or more; for example, at    least 5 days (such as about 5 to 10 days), preferably at least 9    days (such as about 9 to 14 days), more preferably at least about 10    days (such as about 10 to 15 days), or at least about 11 days (such    as about 11 to 16 days), more preferably at least about 12 days    (such as about 12 to 18 days or more), or more than 14 days (such as    about 14 to 19 days).-   Aspect T-14: Derivative according to any of aspects T-1 to T-13,    that is a pegylated derivative.-   Aspect T-15: Compound or construct, that comprises or essentially    consists of one or more derivatives according to any of aspects T-1    to T-14, and optionally further comprises one or more other groups,    residues, moieties or binding units, optionally linked via one or    more linkers.-   Aspect T-16: Compound or construct according to aspect T-15, in    which said one or more other groups, residues, moieties or binding    units are amino acid sequences.-   Aspect T-17: Compound or construct according to aspect T-16, in    which said one or more linkers, if present, are one or more amino    acid sequences.-   Aspect T-18: Nucleic acid encoding a compound or construct according    to aspect T-16 or T-17.-   Aspect T-19: Composition, comprising at least one derivative to any    of aspects T-1 to T-14, compound or construct according to any of    aspects T-15 to T-17, or nucleic acid or nucleotide sequence    according to aspect T-18.    Specifically Preferred Embodiments:-   1. Nanobody that is directed against and/or that can specifically    bind to hOX40L (SEQ ID NO: 175).-   2. Nanobody according to embodiment 1, that is in essentially    isolated form.-   3. Nanobody according to any of embodiments 1 to 2 that can    specifically bind to hOX40L (SEQ ID NO: 175) with a rate of    dissociation (k_(off) rate) between 10⁻² s⁻¹ and 10⁻⁶ s⁻¹.-   4. Nanobody according to any of embodiments 1 to 3 that can    specifically bind to hOX40L (SEQ ID NO: 175) with an affinity less    than 1 nM.-   5. Nanobody that can specifically bind to hOX40L (SEQ ID NO: 175)    and has an IC50 value in the alphascreen assay with 0.12 nM hOX40L    (SEQ ID NO: 175) and 0.2 nM OX40/Fc of less than 10 nM.-   6. Nanobody that can specifically bind to hOX40L (SEQ ID NO: 175)    and has an IC50 value in the FACS assay of less than 50 nM.-   7. Nanobody that can specifically bind to hOX40L (SEQ ID NO: 175)    and has an IC50 value in the T-cell activation assay using human    donors that is less than 200 nM, more preferably less than 100 nM,    most preferred less than 10 nM.-   8. Nanobody according to any of embodiments 1 to 7, that    -   i) has at least 80% amino acid identity with at least one of the        amino acid sequences of SEQ ID NO's: 179 to 185 or 199 to 226,        in which for the purposes of determining the degree of amino        acid identity, the amino acid residues that form the CDR        sequences are disregarded;    -   and in which:    -   ii) preferably one or more of the amino acid residues at        positions 11, 37, 44, 45, 47, 83, 84, 103, 104 and 108 according        to the Kabat numbering are chosen from the Hallmark residues        mentioned in Table B-2.-   9. Nanobody according to any of embodiments 1 to 8, in which:    -   CDR1 is chosen from the group consisting of:    -   a) the amino acid sequences of SEQ ID NO's: 133 to 139;    -   b) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 133 to 139;    -   c) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 133 to 139;    -   and/or    -   CDR2 is chosen from the group consisting of:    -   d) the amino acid sequences of SEQ ID NO's: 147 to 153;    -   e) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 147 to 153;    -   f) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 147 to 153;    -   and/or    -   CDR3 is chosen from the group consisting of:    -   g) the amino acid sequences of SEQ ID NO's: 161 to 167;    -   h) amino acid sequences that have at least 80% amino acid        identity with at least one of the amino acid sequences of SEQ ID        NO's: 161 to 167;    -   i) amino acid sequences that have 3, 2, or 1 amino acid        difference with at least one of the amino acid sequences of SEQ        ID NO's: 161 to 167.-   10. A polypeptide that comprises of one or more Nanobodies according    to any of embodiments 1 to 9, and optionally further comprises one    or more peptidic linkers.-   11. The polypeptide according to embodiment 10, that is chosen from    the group consisting of SEQ ID NO's: 186 to 198 and 227 to 234 or    from the group consisting of from amino acid sequences that have    more than 80% sequence identity with at least one of the amino acid    sequences of SEQ ID NO's: 186 to 198 and 227 to 234.-   12. The polypeptide according to embodiment 10 or 11, that is chosen    from the group consisting of SEQ ID NO's: 186 to 198 and 227 to 234.-   13. The polypeptide according to embodiment 10 or 11, that can    specifically bind to hOX40L (SEQ ID NO: 175) and has an IC50 value    in the T-cell activation assay using human donors that is less than    the IC50 of the benchmark Fab, wherein the benchmark IgG from which    the Fab is derived from has the following light and heavy chains:    SEQ ID NO: 177 and 178.-   14. The polypeptide according to embodiment 10 or 11, that can    specifically bind to hOX40L (SEQ ID NO: 175) and has an IC50 value    in the T-cell activation assay using human donors that is less than    200 nM, more preferably less than 100 nM, even more preferably less    than 50 nM, even more preferably less than 10 nM, most preferred    less than 5 nM.-   15. Method for producing a Nanobody according to any of embodiments    1 to 9, said method at least comprising the steps of expressing, in    a suitable host cell or host organism or in another suitable    expression system, a nucleic acid or nucleotide sequence encoding a    Nanobody according to any of embodiments 1 to 9.-   16. Method for screening amino acid sequences directed against    hOX40L (SEQ ID NO: 175) that comprises at least the steps of:    -   a) providing a set, collection or library of nucleic acid        sequences encoding amino acid sequences;    -   b) screening said set, collection or library of nucleic acid        sequences for nucleic acid sequences that encode an amino acid        sequence that can bind to and/or has affinity for hOX40L (SEQ ID        NO: 175) and that is cross-blocked or is cross blocking a        Nanobody with one of SEQ ID NO's: 179 to 185, or a humanized        Nanobody thereof, e.g. with one of SEQ ID NO's: 199 to 226, or a        polypeptide with one of SEQ ID NO's: 186 to 198 and 227 to 234;        and    -   c) isolating said nucleic acid sequence, followed by expressing        said amino acid sequence.-   17. Nanobody according to any of embodiments 1 to 9 or a polypeptide    according to any of embodiments 10 to 14 for use as a medicament.-   18. Nanobody according of any of embodiments 1 to 9 or a polypeptide    according to any of embodiments 10 to 14 for use in the treatment of    asthma, allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or arthrosclerosis.-   19. A pharmaceutical composition for the treatment of asthma,    allergic asthma, chronic colitis, Crohn's disease, inflammatory    bowel disease, and/or arthrosclerosis comprising a Nanobody    according to any of embodiments 1 to 9 or a polypeptide according to    any of embodiments 10 to 14, and a pharmaceutically acceptable    excipient.-   20. Method for the prevention and/or treatment of at least one    inflammatory disease and/or disorder such as e.g. asthma, allergic    asthma, chronic colitis, Crohn's disease, inflammatory bowel    disease, and/or arthrosclerosis, said method comprising    administering, to a subject in need thereof, a pharmaceutically    active amount of at least one Nanobody according to any of    embodiments 1 to 9 or a polypeptide according to any of embodiments    10 to 14.-   21. Nanobody according to any of embodiments 1 to 9 or a polypeptide    according to any of embodiments 10 to 14 for use in a patient with    severe persistent allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or atherosclerosis who remain    symptomatic despite optimized standard treatment.-   22. A pharmaceutical composition for the treatment of a patient with    severe persistent allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or atherosclerosis who remain    symptomatic despite optimized standard treatment, said treatment    comprising administering a Nanobody according to any of embodiments    1 to 9 or a polypeptide according to any of embodiments 10 to 14,    and a pharmaceutically acceptable excipient.-   23. Method for the prevention and/or treatment of a patient with    severe persistent allergic asthma, chronic colitis, Crohn's disease,    inflammatory bowel disease, and/or atherosclerosis who remain    symptomatic despite optimized standard treatment, said method    comprising administering, to a subject in need thereof, a    pharmaceutically active amount of at least one Nanobody according to    any of embodiments 1 to 9 or a polypeptide according to any of    embodiments 10 to 14.

EXAMPLES Example 1 Identification of OX40L Blocking Nanobodies

1.1 Immunizations

Three llamas (No. 285, 286 and 287) were immunized, according tostandard protocols, with 4 intramuscular injections in the neck (100 or50 μg/dose at biweekly intervals) of human (h) OX40L (extracellulardomain expressed in NSO mouse myeloma cells; R&D Systems, Minneapolis,Minn., USA), formulated in Complete Freund's Adjuvant (day 0) orIncomplete Freund's Adjuvant (following immunizations) (Difco, BDBiosciences, San Jose, Calif., USA). Another three llamas (No. 181b,185b and 189b) were immunized, according to standard protocols, with 4subcutaneous injections in the bow (2×10⁷ cells/dose at biweeklyintervals) of CAKI cells overexpressing hOX40L, formulated in PBS. TheCAKI (camel kidney) cells (Nguyen, Desmyter, Muyldermans, (2001) Adv.Immunol. 79: 261-296) were stably transfected with an expression vectorfor full length human OX40L (SEQ ID NO: 175) using Cell LineNucleofector® Kit V (Amaxa VCA-1003; Lonza, Cologne, Germany). Cellsexpressing the highest levels of hOX40L on their membrane were sortedwith FACSAria™ cell sorter (BD Biosciences) using PE (phycoerythrin)conjugated mouse anti-hOX40L (BD Bioscience) and subsequently culturedin RPMI 1640+10% Fetal Calf Serum+1% Penicillin/Streptomycin+300 μg/mlG418 (Invitrogen, Carlsbad, Calif., USA).

At day 46 or day 50 serum was collected from llamas immunized withrecombinant protein or cells respectively to define antibody titersagainst hOX40L by ELISA and FACS. In ELISA, 96-well Maxisorp plates(Nunc, Wiesbaden, Germany) were coated with hOX40L. After blocking andadding diluted sera samples, the presence of anti-OX40L antibodies wasdemonstrated using mouse anti-llama IgG1, 2 and 3 antisera (in houseproduced) and HRP (horseradish peroxidase) conjugated rabbit anti-mouseIgG (Dako, Glostrup, Denmark) and a subsequent enzymatic reaction in thepresence of the substrate TMB (3,3′,5,5′-tetramentylbenzidine) (Promega,Madison, Wis., USA). In FACS, binding of antibodies present in sera ofimmunized llamas to Chinese Hamster Ovary (CHO) cells overexpressinghOX40L was investigated. CHO K1 (ATCC) cells were stably transfected asdescribed. Cells expressing medium and high levels of hOX40L on theirmembrane were sorted as described and cultured in RPMI 1640+10% FetalCalf Serum+1% Penicillin/Streptomycin+1 mg/ml G418. Cells wereresuspended in diluted serum samples. After washing the presence ofanti-OX40L antibodies was demonstrated in FACSArray™ (BD Biosciences)using goat anti-llama IgG (Bethyl Laboratories, Montgomery, Tex., USA)and PE conjugated donkey anti-goat IgG (Jackson Immuno Research, WestGrove, Pa., USA). Both in ELISA and in FACS high antibody serum titersagainst hOX40L were detected for all llamas.

1.2 Library Construction

Peripheral blood mononuclear cells were prepared from serum samples ofdays 46 and 50 or of days 21, 45 and 50 for llamas immunized withrecombinant protein or cells respectively using Ficoll-Paque Plus (GEHealthcare, Uppsala, Sweden) according to the manufacturer'sinstructions. Except for llamas 181b and 185b, also a LN (lymph node)biopsy was taken on day 45 or 46. Next, total RNA was extracted from theperipheral blood mononuclear cells and from the LN using Rneasy Midi Kit(Qiagen, Venlo, The Netherlands) following manufacturer instructions andused as starting material for RT-PCR to amplify Nanobody encoding genefragments. These fragments were cloned into a house made phagemidvector, allowing production of recombinant phage particles, afterinfection with helper phage, which display the Nanobodies as genelllfusion proteins on the surface of the phage particles. Phage wasprepared according to standard methods and stored after filtersterilization at 4° C. for further use.

1.3 Selections

Phage libraries obtained from llamas No. 285, 286 and 287 were used fordifferent selection strategies.

In a first and second selection round, biotinylated hOX40L [R&D Systems;biotinylated in house according to manufacturer instructions usingSulfo-NHS-LC-Biotin (Pierce, Rockford, Ill., USA)] at 100, 10, 1, 0.1,0.01 nM was incubated with the phage libraries and subsequently capturedon Streptavidin Dynabeads (Invitrogen). Following extensive washing,bound phages were eluted with either 1 mg/ml trypsin or 1 μM hOX40/Fcchimera (extracellular domain of hOX40 fused to Fc of human IgG,expressed in NSO mouse myeloma cells; R&D Systems).

In another first selection, CHO cells or CAKI expressing hOX40L (cellgeneration is described above) were incubated with the phage libraries.After extensive washing, bound phages were eluted from the cells byresuspension in 1 mg/ml trypsin. In a subsequent second selection, phagelibraries were incubated with CAKI cells expressing hOX40L (cellgeneration is described above). After extensive washing, bound phageswere eluted as in the first selection round.

Phage libraries obtained from llamas No. 181b, 185b and 189b were usedfor a first and second round selection on CHO cells expressing hOX40L asdescribed above.

In all selections, enrichment was observed. The output from theselections was rescued in E. coli TG1 cells. Colonies were picked andgrown in 96 deep well plates (1 ml volume) and induced by adding IPTGfor expression of soluble Nanobodies containing a C-terminal c-myc andHis₆ tag. Periplasmic extracts (volume: ˜100 μl) were prepared accordingto standard methods

1.4 Screening for OX40L Blocking Nanobodies in Alphascreen Assay

The periplasmic extracts were screened in an Alphascreen assay toevaluate the blocking capacity of the expressed Nanobodies. This assayrelies on the use of Donor and Acceptor beads which can be conjugated tobiological molecules. When a biological interaction between moleculesbrings the beads into proximity, excited singlet oxygen molecules thatare produced upon laser excitation at 680 nm by a photosensitizer in theDonor bead, diffuse across to react with a chemiluminiscer in theacceptor bead that further activates fluorophores which subsequentlyemit light at 520-620 nm. If the Nanobody inhibits binding of OX40L toOX40, fluorescent output will decrease.

Acceptor beads (Perkin Elmer, Waltham, Mass., USA) were conjugated withanti-human Fc Nanobodies (prepared in house) according to manufacturerinstructions. To evaluate the neutralizing capacity of anti-hOX40LNanobodies, the periplasmic extracts were pre-incubated with 0.37 nMbiotinylated hOX40L for 15 min at room temperature. To this mixture,first the anti-human Fc conjugated acceptor beads and hOX40/Fc (0.2 nMfinal concentration) were added and incubated for 1 hour at roomtemperature. Second, streptavidin donor beads (Perkin Elmer) were addedand incubated for an additional 1 hour. Fluorescence was measured byreading plates on the EnVision Multilabel Plate Reader (Perkin Elmer)using an excitation wavelength of 680 nm and an emission wavelength of520 nm. Decrease in fluorescence signal indicates that the binding ofbiotinylated OX40L to the OX40 receptor is blocked by the Nanobodyexpressed in the periplasmic extract.

From this screening, inhibiting Nanobodies were selected and sequenced.Sequencing analysis revealed 29 Nanobody families, of which 7 wereisolated from llamas immunized with recombinant protein and 22 families,of which 11 contain only one member, were isolated from llamas immunizedwith CAKI cells.

1.5 Binding of OX40L Blocking Nanobodies to Cell Expressed OX40L

Binding of the OX40L blocking Nanobodies to hOX40L expressed on themembrane of cells was determined in a binding FACS assay. CHO cellsexpressing full length hOX40L (see above) or wild type CHO K1 cells wereresuspended in diluted periplasmic extract and incubated for 30 min at4° C. After washing bound Nanobodies were detected in FACSArray™ usingmouse anti-c-myc (Serotec, Dusseldorf, Germany) and PE conjugated goatanti-mouse IgG (Jackson Immuno Research). Strong and specific bindingsignals on CHO cells expressing hOX40L were demonstrated for all membersof 6 families obtained from llamas immunized with recombinant proteinand 14 families obtained from llamas immunized with cells. A relativeweak binding signal was obtained for all OX40L blocking Nanobodies ofthe remaining families.

Example 2 Characterization of OX40L Blocking Nanobodies in Alphascreen,Competition FACS and T-Cell Activation Assay

2.1 Nanobody Expression and Purification

7 inhibitory Nanobodies (3 obtained from recombinant proteinimmunizations and 4 from cell immunizations) selected from the screeningdescribed in example 1 were further purified and characterized (SEQ IDNO's: 179 to 185, see also Table A-1). Selected Nanobodies wereexpressed in E. coli as c-myc, His₆-tagged proteins in a culture volumeof 250 mL. Expression was induced by addition of 1 mM IPTG and allowedto continue for 4 hours at 37° C. After spinning the cell cultures,periplasmic extracts were prepared by freeze-thawing of the pellets andresuspension in PBS. These extracts were used as starting material forimmobilized metal ion affinity chromatography (IMAC) using a HisTrap™crude column (GE Healthcare). Nanobodies were eluted from the columnusing imidazole step gradient from 20 mM to 250 mM. In a next step theNanobodies were desalted using HiPrep™ 26/10 desalting columns (GEHealthcare) in D-PBS (Invitrogen). Finally, lipopolysaccharides (LPS)were removed through incubation for 1 hour at room temperature with 50mM octyl-β-D-glucopiranoside (OGP; Sigma, Bornem, Belgium) and gelfiltration on Superdex 75 10/300GL column (GE Healthcare).

2.2 OX40L Blocking Benchmark Antibody Generation

In all assays for characterization of OX40L blocking Nanobodiesdescribed below, the potency was compared with a benchmark OX40Lblocking mAb (monoclonal antibody) (benchmark IgG (SEQ ID NO: 177 (heavychain)+SEQ ID NO: 178 (light chain)). A pEE mammalian expression vectorcontaining DNA coding for benchmark antibody was constructed by firstcloning the DNA coding for the heavy chain and light chain into pEE6.4and pEE12.4 respectively (Lonza, Basel, Switzerland) and thenconstructing a double-gene vector. Human embryonic kidney cells(HEK293T; DSMZ, Braunschweig, Germany) were grown in DMEM+Glutamaxlmedium (Invitrogen) supplemented with 10% fetal bovine serum (FBS) and1% Penicillin/Streptomycin. HEK293T cells were transiently transfectedwith the plasmid expressing the heavy and light chain of anti-OX40Lbenchmark mAb using poly-ethylene imine (Polysciences, Eppelheim,Germany) and DMEM+Glutamaxl medium according to manufacturer'sinstructions and the conditioned medium was harvested after 5 daysincubation at 37° C. in a CO₂ incubator. The medium was centrifuged andthe supernatant was purified on Mabselect Sure column (GE Healthcare),eluted with 50 mM Na₃Citrate pH 3.0, immediately neutralized with 1MTris-HCl pH 9 and dialyzed against PBS.

The Fab fragment of the benchmark was prepared by papain digest of thebenchmark IgG (SEQ ID NO: 177 (heavy chain)+SEQ ID NO: 178 (lightchain)). Briefly, the IgG was incubated for 4 hours at 37° C. indigestion buffer (0.1M Na₂HPO₄; 0.1M KH₂PO₄; pH:7.3) containing 15 mMcystein, 2 mM EDTA and papain (1/100 of total amount IgG). UndigestedIgG and Fc fragment were immediately removed on a Mabselect Sure columnand the flow-through was further purified via size exclusion on aSuperdex 75 10/300GL column and subsequently via affinity chromatographyusing a CaptureSelect Fab kappa matrix (BAC, Naarden, The Netherlands).Fab fragments were eluted with 100 mM glycin pH2.5, immediatelyneutralized by the addition of 1M Tris-HCl pH7.5 and dialyzed againstPBS.

2.3 Nanobodies Block the Binding of OX40L to its Cognate Receptor OX40in Alphascreen

The purified Nanobodies were characterized in an Alphascreen assay toevaluate their blocking capacity and compare this with a benchmark OX40Lblocking antibody.

Acceptor beads were conjugated with anti-human Fc Nanobodies and hOX40Lwas biotinlyated as described in Example 1. A dilution series ofanti-OX40L Nanobodies or anti-OX40L benchmark Fab starting from 250 nMup to 0.9 pM was pre-incubated with 120 pM biotinylated hOX40L during 15minutes at RT. To this mixture, first the anti-human Fc conjugatedacceptor beads and hOX40/Fc (0.2 nM final concentration) were added andincubated for 1 hour at room temperature. Next, streptavidin donor beadswere added and incubated for an additional 1 hour. Fluorescence wasmeasured by reading plates on the EnVision Multilabel Plate Reader usingan excitation wavelength of 680 nm and an emission wavelength of 520 nm.

Preincubation of all Nanobodies with biotinylated hOX40L reducedfluorescence intensity at 520 nm, demonstrating that the Nanobodies caneffectively inhibit OX40L binding to OX40 in a dose-dependent manner.The calculated IC50 values are shown in Table C-1, and vary from 112 pMfor OX40L18E09 up to 540 pM for OX40L19A07.

2.4 Nanobodies Block the Binding of OX40 to CHO Cells Expressing OX40Lin FACS

The purified Nanobodies were characterized in a competition FACS assayto evaluate their blocking capacity using native OX40L expressed oncells.

A dilution series of anti-OX40L Nanobodies or anti-OX40L benchmark Fabstarting from 1.2 μM up to 6.8 pM was pre-incubated with 3.1 nM hOX40/Fcand 2×10⁵ hOX40L expressing cells for 30 min at 4° C. After washingbound hOX40/Fc was detected in FACSArray™ using PE conjugated anti-humanIgG (Jackson Immuno Research).

All Nanobodies reduced fluorescence intensity, demonstrating that theNanobodies can effectively inhibit OX40 binding to native, membraneexpressed OX40L in a dose-dependent manner. The calculated 1050 valuesare shown in Table C-1, and vary from 1.61 nM for OX40L15B07 up to 16.55nM for OX40L19A07.

2.5 Nanobodies Block OX40L Mediated Effector Memory T-Cell Activation

The purified Nanobodies were characterized in a T-cell activation assayto evaluate their capacity of blocking OX40L mediated activation ofeffector memory T-cells.

CD45RA-CCR7-effector memory T-cells were isolated from buffy coats (RedCross, Ghent, Belgium) from healthy donors in two steps. First, thetotal T-cell population was isolated using RosetteSep Human T-cellEnrichment Cocktail (StemCell Technologies, Vancouver, Canada) andFicoll-Paque™ PLUS (GE Healthcare) following manufacturer instructions.In a second step a negative selection for CD45RA− CCR7-cells wasperformed by staining CD45RA+ CCR7+ cells with mouse anti-humanCD45RA-biotin (BD Biosciences) and rat anti-human CCR7-biotin (BSBiosciences) and incubation with Dynabeads Biotin Binder (Invitrogen)according to manufacturer instructions.

Wells of a microtiterplate (Greiner, Frickenhausen, Germany) were coatedovernight at 4° C. with 31.25 ng/ml anti-CD3 mAb OKT-3 (eBioscience, SanDiego, USA). After washing the plate, 2×10⁵ CD45RA− CCR7-effector memoryT-cells, 1×10⁴ hOX40L expressing CHO cells or wild type CHO cells(irradiated with gamma scintillator at 3000 RAD; UZ Gent, Belgium) anddilution series of anti-OX40L Nanobodies or anti-OX40L benchmark Fabstarting from 2 μM in medium (RPMI+10% Fetal Calf Serum+1%Penicillin/Streptomycin) were added simultaneously and incubated for 3days at 37° C. in CO₂ incubator.

Production of IL4 by CD45RA− CCR7-effector memory T-cells was measuredin ELISA. Wells of a Maxisorp plate (Nunc, Langenselbold, Germany) werecoated overnight at 4° C. with 2 μg/ml anti-human IL4 (ELISA Capture)(BD Biosciences). After washing and blocking of the coated wells, a ½dilution of cell supernatant was added together with 1 μg/mlbiotinylated anti-human IL4 (BD Biosciences) and incubated for 2.5 hoursat room temperature. As a standard, ½ serial dilutions of recombinanthuman IL4 (BD Biosciences) starting from 625 pg/ml were included.Detection was done using HRP conjugated streptavidin (Dako) and TMB OneSolution (Promega). The reaction was stopped with H₂SO₄ and the OD wasread at 450 nm.

All Nanobodies effectively inhibit OX40L mediated CD45RA− CCR7-effectormemory T-cell activation. The calculated IC50 values are shown in TableC-2 for 4 human donors and vary from 36-49 nM for OX40L18E09 up to596-618 nM for OX40L19A07.

Example 3 Binding Specificity of OX40L Blocking Nanobodies

3.1 OX40L Blocking Nanobodies Bind Specifically to Cell MembraneExpressed Human and Cynomolgus OX40L

OX40L of human (hOX40L) and cynomolgus monkey (cynoOX40L) was expressedon CHO cells as full length, membrane-bound protein. Transfection of CHOK1 with the respective expression plasmid DNA and selection of cloneswith high expression levels was performed as described in Example 1.Binding of the Nanobodies to the cell surface expressed OX40L wasassessed by FACS analysis of cells as described below.

A dilution series of anti-OX40L Nanobodies or anti-OX40L benchmark Fabstarting from 200 nM was pre-incubated with 2×10⁵ either hOX40L orcynoOX40L expressing CHO cells for 30 min at 4° C. After washing boundNanobodies were detected in FACSArray™ using mouse anti-c-myc and PEconjugated goat anti-mouse IgG.

All Nanobodies showed dose-dependent binding to both hOX40L andcynoOX40L expressed on CHO cells (Table C-3).

3.2 OX40L Blocking Nanobodies do not Bind to TNF Family MembersTNF-Alpha, CD40L, CD30L, RANKL or TRAIL

The binding of OX40L blocking Nanobodies to other TNF family members wastested in a competition ELISA.

Biotinylated hOX40L was captured on a Maxisorp plate coated with 2 μg/mlneutravidin. A fixed concentration of Nanobody [EC50 concentration asdetermined in binding ELISA to neutravidin captured hOX40L (data notshown): ranging from 1.3 nM to 4.7 nM] was pre-incubated for 1 hour atroom temperature with a concentration series, starting from 100 foldmolar excess, of hTNF-alpha (in house produced), hCD40L (PeproTech,Rocky Hill, N.J., USA), hCD30L (R&D Systems), human Receptor Activatorfor Nuclear Factor κ B Ligand (hRANKL; PeproTech), human tumor necrosisfactor-related apoptosis inducing ligand (hTRAIL; R&D Systems) or hOX40Las positive control, before they were added to the plate. Binding of theNanobodies to neutravidin captured hOX40L was detected with polyclonalrabbit anti-VHH antiserum (in house produced) and HRP conjugated goatanti-rabbit IgG (Dako). Detection was done using sTMB (SDT Reagents,Baesweiler, Germany), the reaction was stopped with 1M HCl andabsorbance was determined at 450 nm.

Binding of the Nanobodies to hOX40L captured on neutravidin was onlyinhibited by exogenously added hOX40L and was not affected by theaddition of the other ligands. Results obtained for OX40L01E07 are shownin FIG. 1 and are representative for all 7 Nanobodies tested.

Example 4 Characterization of Trivalent Bispecific Anti-OX40L Nanobodiesin Alphascreen, Competition FACS and T-Cell Activation Assay

4.1 Construction and Expression of Trivalent Bispecific Anti-OX40LNanobodies

OX40L01B11, OX40L01E07, OX40L01E10, OX40L15B07, OX40L18E09, OX40L19D08and OX40L19A07 were formatted as trivalent bispecific anti-OX40LNanobodies. The trivalent molecules comprise two identical anti-OX40LNanobody building blocks and one anti-human serum albumin (HSA)Nanobody, ALB11, for half life extension. ALB11 was either positioned inthe middle or at the C-terminus of the trivalent constructs, and thelinker between the building blocks was either 9GS (Gly₄SerGly₃Ser) or35GS ((Gly₄Ser)₅). The sequences of the trivalent bispecific anti-OX40LNanobodies are shown in Table A-3 (SEQ ID NO's: 186 to 198). Theseconstructs were expressed in Pichia pastoris X-33. A 40 ml pre-culturein YPD medium (20% peptone, 10% yeast extract and 2% dextrose) wasincubated for 8 hours at 28° C. at 250 rpm. Fresh medium (500 ml BGCM;2% peptone, 1% yeast extract, 0.2 M K-phosphate pH 6, 1% glycerol, 1.3%Yeast Nitrogen Base (Invitrogen), 0.2 mg biotin] was inoculated to anOD_(600 nm) of 0.08 and incubated overnight at 28° C. at 200 rpm. Thecells were centrifuged when the 20<OD_(600 nm)<25 and the pellet wasresuspended in 160 ml BMCM medium (2.3% peptone, 1.2% yeast extract, 0.2M K phosphate pH 6, 1.3% Yeast Nitrogen Base, 0.06 mg biotin, 0.5%methanol). The culture was incubated for 48 hours at 28° C., 200 rpm andduring that time methanol was added 4 times. The culture was centrifugedand the supernatant was used as starting material for IMAC using aHisTrap™ crude column (GE Healthcare) in the case when a c-myc, His₆ tagwas present at the C-terminus. In the case when there were no tagspresent, the Nanobodies were purified using MEP Hypercell (Pall) orMabSelectSure (GE Healthcare) resin. If necessary, lipopolysaccharideswere removed by incubation with OGP and purification via SEC usingHiLoad_16/60_Superdex75 column (GE Healthcare).

4.2 Inhibition of OX40L Binding to OX40 by Trivalent BispecificAnti-OX40L Nanobodies in AlphaScreen

The trivalent Nanobodies (OX40L003, OX40L004, OX40L005, OX40L006,OX40L007, OX40L008, OX40L009, OX40L033, OX40L034, OX40L035, OX40L036,OX40L037, OX40L038) were compared to their monovalent counterparts inthe AlphaScreen assay to evaluate whether they could also block OX40Lbinding to its cognate receptor.

AlphaScreen was performed as described in example 2, using 31 pMbiotinylated hOX40L and 80 pM OX40/Fc. All trivalent Nanobodies blockedOX40L binding to the OX40 receptor in a dose dependent way withincreased potency as compared to the corresponding monovalent molecules(see Table C-4). The calculated IC50 values for the trivalent Nanobodiesvaried from 11 pM for OX40L038 up to 95 pM for OX40L008.

In addition, the potency of the trivalent Nanobodies was also determinedin presence of HSA. Nanobodies were pre-incubated for 1 hour at roomtemperature with 5 μM HSA (Sigma, Bornem, Belgium) prior to the additionof beads and hOX40/Fc. Final concentration of HSA in the assay was 1 μM.As shown in Table C-4, the potency of all trivalent Nanobodies forblocking OX40L-OX40 interaction was not significantly affected in thepresence of HSA.

4.3 Inhibition of OX40 Binding to OX40L Expressed on CHO Cell Membranesby Trivalent Bispecific Anti-OX40L Nanobodies in FACS

The trivalent Nanobodies (OX40L003, OX40L004, OX40L005, OX40L006,OX40L007, OX40L008, OX40L009) were compared to their monovalentcounterparts in a competition FACS assay to evaluate whether they couldalso block binding of OX40 to OX40L expressed on CHO cell membrane.

The competition FACS assay was performed as described in example 2. Alltrivalent Nanobodies effectively inhibited OX40 binding to native,membrane expressed OX40L in a dose-dependent manner with potenciescomparable with the corresponding monovalent molecules (see Table C-4).This might be explained by the low sensitivity of the assay due to highexpression level of hOX40L on the CHO cells.

4.4 Binding to HSA

The affinity of the trivalent Nanobodies (OX40L003, OX40L004, OX40L005,OX40L006, OX40L007, OX40L008, OX40L009, OX40L034) for HSA was measuredin BIAcore T100 instrument. HSA was immobilized via amine coupling on aCM-5 sensorchip at 626RU. Different concentrations of Nanobodies,ranging between 2 nM and 400 nM, were injected at 45 μl/min for 2 min,including a dissociation time of 10 min and regeneration of the surfacewith 10 mM Glycine-HCl pH1.5. Fitting was done using the 1:1 bindingmodel and kinetic parameters are listed in Table C-5. The affinity ofall trivalent Nanobodies for HSA is comparable.

4.5 Inhibition of OX40L Mediated Effector Memory T-Cell Activation byTrivalent Bispecific Anti-OX40L Nanobodies

The trivalent Nanobodies (OX40L003, OX40L004, OX40L005, OX40L006,OX40L007, OX40L008, OX40L009, OX40L033, OX40L034, OX40L035, OX40L036,OX40L037, OX40L038) were compared to their monovalent counterparts in aT-cell activation assay to evaluate their capacity of blocking OX40Lmediated activation of effector memory T-cells.

The T-cell activation assay was performed as described in Example 2,using four different human donors (donor 1-4). To investigate theinfluence of HSA binding on the potency of trivalent anti-OX40LNanobodies, the same T-cell activation was performed in an additional 4donors (donor 5-8) in the presence of 10% human serum (HS). Thecalculated IC50 values are shown in Table C-6. The inhibition curvesobtained for donor 3 are shown in FIG. 2 and are representative for alldonors tested.

All trivalent Nanobodies effectively inhibit OX40L mediated CD45RA−CCR7-effector memory T-cell activation with increased potencies comparedto the monovalent Nanobodies. For the trivalent Nanobodies containingthe OX40L01E07 building block, the potency in presence of HSA wasincreased when the ALB11 was at the C-terminal position. Furthermore, a35GS linker between the last anti-OX40L building block and ALB11(OX40L034) was preferred above a 9GS linker (OX40L033). Also forOX40L01E10, the formats with ALB11 at C-terminus had higher potency inpresence of HSA, but there was no clear difference between OX40L035 andOX40L036. Finally, for the OX40L15B07 containing trivalent Nanobodies,all formats had similar potency in the presence of HSA, regardless ofthe position of ALB11 and the linker length.

Example 5 Epitope Binning of Anti-OX40L Nanobodies

Epitope binning of the 7 Nanobodies was determined using Surface PlasmonResonance on a Biacore T100 instrument. The experiment was performed inHBS-EP+ runningbuffer at 25° C. Recombinant hOX40L (R&D Systems) wasimmobilized on a Sensorchip CM5 via amine coupling at a level of app.1200 RU. A first injection at 10 μl/min for 2 min with 500 nM of theNanobody was performed. After a dissociation of 10 sec, a dual injectionwas performed at 10 μl/min for 2 min, starting with 1 μM of the sameNanobody to ensure saturation of the surface, followed by a mixture of 1μM of the Nanobody and 500 nM of anti-OX40L benchmark Fab. After 10 mindissociation, regeneration of the surface was performed by injection of50 mM NaOH for 5-25 sec at 100 μl/. Based on the data shown in TableC-7, it was concluded that OX40L01B11 and the anti-OX40L benchmark Fabrecognize the same or overlapping epitope on hOX40L or they aresterically hindering each other as they could not bind simultaneously tohOX40L. The data also indicate that the epitope of the other Nanobodiesdoes not completely overlap with the epitope of anti-OX40L benchmark Faband/or to a smaller or larger extend sterical hindrance is presentdependent on the Nanobody injected.

In addition, it was investigated to what extend the 7 anti-OX40LNanobodies have a different or identical or overlapping epitope.Standard conditions were as described above. Recombinant hOX40L wasimmobilized on a Sensorchip CM5 via amine coupling at a level of app.1300 RU. A dual injection was performed at 10 μl/min for 2 min, startingwith 500 nM of the first Nanobody, followed by 500 nM of the secondNanobody. After 10 min dissociation, regeneration of the surface wasperformed by injection of 50 mM NaOH for 5-20 sec at 100 μl/min. Asshown in Table C-8, significant binding responses were obtained byinjecting OX40L19D08, OX40L19A07 and OX40L01E07 after a first injectionwith OX40L01B11. Furthermore, OX40L15B07 and OX40L18E09 cannot bindsimultaneously to hOX40L.

Example 6 Sequence Optimization of Anti-OX40L Nanobodies

In general, during Nanobody sequence optimization, parental wild typeNanobody® sequences are mutated to yield Nanobody® sequences that aremore identical to human VH3-JH germline consensus sequences. Specificamino acids in the framework regions that differ between the Nanobody®and the human VH3-JH germline consensus are altered to the humancounterpart in such a way that the protein structure, activity andstability are kept intact. To investigate this, all sequenceoptimization variants were compared with the parental Nanobody in fourdifferent assays: (i) determination of the melting temperature (Tm) in aThermal Shift Assay (TSA), (ii) analysis of in vitro potency inhOX40L/hOX40 competition Alphascreen under native conditions as well asafter heating for 1 min at Tm+10° C., (iii) analysis of in vitro potencyin T-cell activation assay and (iv) analytical size exclusion (SEC)analysis.

In the TSA assay, Nanobodies were diluted to a concentration of 0.2mg/ml and melting temperature (Tm) was determined at different pH bystepwise increase in temperature in presence of Sypro Orange, a dye thatbinds to Trp residues that become exposed upon unfolding of the protein,using the Lightcycler (Roche) for detection. The OX40L/hOX40 Alphascreenwas exactly performed as described in Example 2. The T-cell activationassay was essentially performed as described in Example 2, but 5 nM rechOX40L instead of hOX40L expressing CHO cells and 2 μg/ml anti-CD3 mAbOKT-3 was used. In SEC analysis, the Nanobodies were analyzed on aPhenomenex matrix to allow detection of multimers, aggregates or‘stickyness’.

6.1 Sequence Optimization of OX40L15B07

For sequence optimization of OX40L15B07, the following mutations wereinvestigated: E1D, A14P, H39Q, R40A, T41P, E43K, G60A, F62S, 171R, A74S,N82bS, K83R and Q108L. Starting from a basic variant, i.e. OX40L15B07(A14P, K83R, Q108L), a library was constructed including 7 additionalmutations (parental or human residue) spread over 7 individualpositions: H39Q, R40A, T41P, E43K, I71R, A74S and N82bS. The library wascloned in an in-house E. coli expression vector and periplasmic extractscontaining soluble Nanobodies of 400 clones were screened in ahOX40L/hOX40 competition Alphascreen, as described in Example 1.Sequence analysis revealed that only the H39Q mutation resulted in adramatic loss of potency, whereas all other mutations did not affect thepotency in this Alphascreen. In addition, a BIAcore off-rate analysiswas performed on BIAcore T100. For this, rec. hOX40L was immobilized ona CM-5 sensorchip. Periplasmic extracts (10-fold diluted) were injectedat 45 μl/min for 120s, followed by a dissociation phase of 600s. Thechip was regenerated with 50 mM NaOH. A ˜2-fold increase in off-rate wasdemonstrated for R40A, T41P and E43K mutations. All other mutationsinvestigated did not affect the off-rate.

Next, different sequence optimization variants (OX40L030, OX40L040-50,OX40L053, OX40L054, OX40L055, OX40L056, OX40L069, OX40L070, OX40L071,OX40L082 and OX40L083; SEQ ID NO's: 206-226; Table A-2) were constructedand produced as described in Example 2. As summarized in Table C-11,E1D, A14P, A74S, K83R and Q108L mutations had no clear effect on potencyor thermal stability. In contrast, a ˜6-fold drop in potency (T-cellassay) and a 5° C. drop in Tm were observed for R40A. T41P and E43Kresulted in a ˜2- and ˜3-fold drop in potency and a 1.5-3° C. and 1-4°C. drop in Tm respectively. The mutations G60A and F62S did not affectthe Tm, but G60A resulted in a ˜3.5-fold drop in potency. Finally, I71Rand N82bS resulted in a drop in Tm of 5° C. and 2° C. respectively, butdid not affect potency. Regardless of the observed decrease in Tm, thepotency of native and heat-treated samples measured in Alphascreen wassimilar for each variant.

Furthermore, the behaviour of OX40L030, OX40L082 and OX40L083 inanalytic SEC on Phenomenex matrix was similar to that of OX40L15B07. Nosignificant aggregation or stickyness was observed, although forOX40L082 a very small prepeak was observed, which might be due todimerization (data not shown).

6.2 Sequence Optimization of OX40L01B11

For sequence optimization of OX40L01B11, the following mutations wereinvestigated: E1D, A14P, V23A, A74S, K83R and Q108L (amino acid positionreferring to Kabat numbering scheme). An OX40L01B11 variant containingall mutations (OX40L075; SEQ ID NO: 199; Table A-2) was constructed andproduced as described in Example 2. As shown in Table C-9, the mutationshad no effect on the potency in a hOX40L/hOX40 competition Alphascreen,but a small drop in Tm of 2° C. compared to the parental OX40L01B11, andan entailed 6-fold drop in potency after heat-treatment of OX40L075 wasobserved. The behaviour of OX40L075 in analytical SEC on Phenomenexmatrix was similar to that of OX40L01B11; no aggregation or stickynesswas observed (data not shown).

6.3 Sequence Optimization of OX40L01E07

For sequence optimization of OX40L01E07, the following mutations wereinvestigated: E1D, A14P, A74S, K83R, L105Q and Q108L. Six OX40L01E07variants (OX40L024, OX40L025, OX40L026, OX40L027, OX40L028 and OX40L039;SEQ ID NO's: 200-205; Table A-2) were constructed and produced asdescribed in Example 2. All the mutations were permissive for in vitropotency in both native conditions and after heat-treatment. Nosignificant negative effect on physical stability was observed (TableC-10). The behaviour of all variants in analytic SEC on Phenomenexmatrix was similar to that of OX40L01E07; no aggregation or stickynesswas observed (data not shown).

Example 7 Characterization of Trivalent Bispecific Sequence OptimizedAnti-OX40L Nanobodies in Alphascreen and T-Cell Activation Assay

7.1 Construction and Expression of Trivalent Bispecific SequenceOptimized Anti-OX40L Nanobodies

Sequence optimized variants of OX40L01B11, OX40L01E07 and OX40L15B07were formatted as trivalent bispecific sequence optimized anti-OX40LNanobodies. The trivalent molecules comprised two identical anti-OX40LNanobody building blocks and one anti-HSA Nanobody, ALB11, for half lifeextension. ALB11 was either positioned in the middle or at theC-terminus of the trivalent constructs, and the linker between thebuilding blocks was either 9GS or 35GS. The sequences of the trivalentbispecific sequence optimized anti-OX40L Nanobodies are shown in TableA-4 (SEQ ID NOs: 227-234).

7.2 Inhibition of OX40L Mediated Effector Memory T-Cell Activation byTrivalent Bispecific Sequence Optimized Anti-OX40L Nanobodies

The in vitro potency of the trivalent bispecific sequence optimizedanti-OX40L Nanobodies (OX40L032, OX40L051, OX40L079, OX40L080, OX40L084,OX40L085 and OX40L086) was compared with the potency of thecorresponding wild type formatted Nanobodies and the anti-OX40Lbenchmark in the T-cell activation assay. The assay was performed asdescribed in Example 4, in the presence of 10% fetal bovine serum or 10%human serum. The data obtained with five different human donors (donor9-13) are shown in Table C-12. The trivalent bispecific sequenceoptimized Nanobodies OX40L079 and OX40L080 had similar potenciescompared to that of wild type OX40L003 in absence of HSA. For bothNanobodies there was a shift in potency in presence of HSA, which wasslightly more pronounced when ALB11 building block was in the middleposition (OX40L080) compared to when it was at the C-terminus(OX40L079). When comparing OX40L003 with OX40L080, however, it seemsthat 35GS linkers instead of 9GS linkers between the respectiveanti-OX40L building blocks on the one hand and ALB11 on the other handdecreased the ‘HSA-effect’.

The trivalent bispecific sequence optimized Nanobodies OX40L032,OX40L051 and OX40L086 had similar potency compared with wild typeOX40L009, both in presence and absence of HSA. Furthermore, the E1Dmutation included in OX40L086 did not affect the potency.

Although a ˜2-fold decrease in potency in Alphascreen was observed forsequence optimized variant OX40L082 compared with the parental NanobodyOX40L15B07 (see Example 6), upon formatting (OX40L084), the potency wassimilar compared to wild type OX40L007. For another sequence optimizedvariant, OX40L083, a ˜6-fold drop in potency was observed in Alphascreen(see Example 6), which was translated in a 15- to 20-fold drop inpotency in the T-cell assay for the trivalent OX40L085 compared withwild type OX40L007. For neither OX40L084 nor OX40L085 the potency inpresence of HSA was affected.

7.3 Binding to HSA

The affinity of the trivalent bispecific sequence optimized Nanobodies(OX40L032, OX40L051, OX40L079, OX40L080, OX40L084 and OX40L085) for HSAwas measured in BIAcore T100 instrument. HSA was immobilized via aminecoupling on a CM-5 sensorchip at 626RU. Different concentrations ofNanobodies, ranging between 2 nM and 400 nM, were injected at 45 μl/minfor 2 min, including a dissociation time of 10 min and regeneration ofthe surface with 10 mM Glycine-HCl pH1.5. Fitting was done using the 1:1binding model and kinetic parameters are listed in Table C-13. Theaffinity of all trivalent Nanobodies for HSA was comparable and theposition of ALB11 did not seem to have an influence on the affinity forHSA.

Tables

TABLE A-1 Preferred VHH sequences or Nanobody sequences(also referred herein as a sequence with aparticular name or SEQ ID NO: X, wherein X isa number referring to the relevant amino acid sequence): SEQ ID NO:X, wherein Name X = Amino acid sequence OX40L15807 179EVQLVESGGGLVQAGGSLRLSCAASRS IGRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISIDNAKNTVYLQ MNNLKPEDTAVYYCNFNKYVTSRDTWG QGTQVTVSSOX40L01B11 180 EVQLVESGGGLVQAGGSLRLSCVASGR SFSTYIMGWFRQAPGKEREFVATISRSGITTRSADSVKGRFTISRDNAKNTVYL QMNSLKPEDTAVYYCAAGPYVEQTLGLYQTLGPWDYWGQGTQVTVSS OX40L01E07 181 EVQLVESGGGLVQAGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREFVAAISR SGRSTSYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAVGGATTVTA SEWDYWGLGTQVTVSS OX40L01E10 182EVQLVESGGGLVQAGDSLRLSCAASGL TFSSFAMGWFRQAPGKEREFVAAISRSGYGTSEADSVRDRFIISRDNAKNTVTL HLSRLKPEDTAVYYCAAEHTLGRPSRSQINYLYWGQGTQVTVSS OX40L18E09 183 EVQLVESGGGLVQAGGSLRLSCAASRNILSLNTMGWYRHAPGKPRELVARISSN SKTDYADSVKGRFTISRDNAKNTVLLQMNSLKPEDTGVYYCNLNVWRTSSDYWG QGTQVTVSS OX40L19A07 184EVQLVESGGGLVQAGGSLRLSCAASGF TLDDYAIAWFRQAPGKEREGVSRIKISNGRTTYAGSVKGRFTISSDNAKNTVYL QMNSLNAEDTAVYYCAADRSSLLFGSNWDRKARYDYWGQGTQVTVSS OX40L19D08 185 EVQLVESGGGLVQAGASLRLSCAASGRRFISNYAMGWFRQAPGQERAFVAAISR SGSITYYTDSVKGRFSISRDYAKSTVYLQMDNLKPEDTAVYYCAADGGAVRDLT TNLPDYWGRGTQVTVSS

TABLE A-2 Sequence optimized Nanobody sequences Name SEQ ID NOAmino acid sequence OX40L075 199 EVQLVESGGGLVQPGGSLRLSCAASGRSFSTYIMGWFRQAPGKEREFVATISRSGI TTRSADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYYCAAGPYVEQTLGLYQTL GPWDYWGQGTLVTVSS OX40L024 200EVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGLGTLVTVSSOX40L025 201 EVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNSKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGLGTLVTVSSOX40L026 202 EVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGQGTLVTVSSOX40L027 203 EVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNSKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGQGTLVTVSSOX40L028 204 DVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGLGTLVTVSSOX40L039 205 DVQLVESGGGLVQPGGSLRLSCAASGRT FSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNSKNTVYLQM NSLRPEDTAVYYCAAVGGATTVTASEWD YWGQGTLVTVSSOX40L030 206 DVQLVESGGGLVQAGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNN LKPEDTAVYYCNFNKYVTSRDTWGQGTQ VTVSS OX40L040207 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L041208 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHATGEPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L042209 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGEPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L043210 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGKPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L044211 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHAPGEPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L045212 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHATGKPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L046213 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L047214 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHAPGKPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L048215 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYADFVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L049216 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDSVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L050217 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYADSVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L053218 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISIDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L054219 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISRDNAKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L055220 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISRDNSKNTVYLQMNN LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L056221 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYADSVKGRFTISRDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L069222 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYADSVKGRFTISIDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L070223 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYADSVKGRFTISRDNSKNTVYLQMNN LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L071224 DVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYADSVKGRFTISIDNSKNTVYLQMNN LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L082225 EVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGEPRELVATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS OX40L083226 EVQLVESGGGLVQPGGSLRLSCAASRSI GRLDRMGWYRHRPGKPRELVATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNS LRPEDTAVYYCNFNKYVTSRDTWGQGTL VTVSS

TABLE A-3 Preferred polypeptide or compound sequences(also referred herein as a sequence with a particularname or SEQ ID NO: X, wherein X is a numberreferring to the relevant amino acid sequence): SEQ ID NO: X, whereinName X = Amino acid sequence OX40L003 186EVQLVESGGGLVQAGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREF (OX40L01E07-VAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYY 9GS-Alb8-9GS-CAAVGGATTVTASEWDYWGLGTQVTVSSGGGGSGGGSEVQLVESGGGL OX40L01E07)VQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAVGGATTVTASEWDYWGLGTQVTVSS OX40L004 187EVQLVESGGGLVQAGGSLRLSCAASRNILSLNTMGWYRHAPGKPRELV (OX40L18E09-ARISSNSKTDYADSVKGRFTISRDNAKNTVLLQMNSLKPEDTGVYYCN 9GS-Alb8-9GS-LNVWRTSSDYWGQGTQVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSL OX40L18E09)RLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGGSLRLSCAASRNILSLNTMGWYRHAPGKPRELVARISSNSKTDYADSVKGRFTISRDNAKNTVLLQMNSLKPEDTGVYYCNLNVWRTSSDYWGQGTQVTVSS OX40L005 188EVQLVESGGGLVQAGASLRLSCAASGRRFISNYAMGWFRQAPGQERAF (OX40L19D08-VAAISRSGSITYYTDSVKGRFSISRDYAKSTVYLQMDNLKPEDTAVYY 9GS-Alb8-9GS-CAADGGAVRDLTTNLPDYWGRGTQVTVSSGGGGSGGGSEVQLVESGGG OX40L19D08)LVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGASLRLSCAASGRRFISNYAMGWFRQAPGQERAFVAAISRSGSITYYTDSVKGRFSISRDYAKSTVYLQMDNLKPEDTAVYYCAADGGAVRDLTTNLPDYWGRGTQVTVSS OX40L006 189EVQLVESGGGLVQAGDSLRLSCAASGLTFSSFAMGWFRQAPGKEREFV (OX40L01E10-AAISRSGYGTSEADSVRDRFIISRDNAKNTVTLHLSRLKPEDTAVYYC 9GS-Alb8-9GS-AAEHTLGRPSRSQ1NYLYWGQGTQVTVSSGGGGSGGGSEVQLVESGGG OX40L01E10)LVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGDSLRLSCAASGLTFSSFAMGWFRQAPGKEREFVAAISRSGYGTSEADSVRDRFIISRDNAKNTVTLHLSRLKPEDTAVYYCAAEHTLGRPSRSQINYLYWGQGTQVTVSS OX40L007 190EVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHRTGEPRELV (OX40L15B07-ATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPEDTAVYYCN 9GS-Alb8-9GS-FNKYVTSRDTWGQGTQVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSL OX40L15B07)RLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHRTGEPRELVATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPEDTAVYYCNFNKYVTSRDTWGQGTQVTVSS OX40L008 191EVQLVESGGGLVQAGGSLRLSCAASGFTLDDYAIAWFRQAPGKEREGV (OX40L19A07-SRIKISNGRTTYAGSVKGRFTISSDNAKNTVYLQMNSLNAEDTAVYYC 9GS-Alb8-9GS-AADRSSLLFGSNWDRKARYDYWGQGTQVTVSSGGGGSGGGSEVQLVES OX40L19A07)GGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGGSLRLSCAASGFTLDDYAIAWFRQAPGKEREGVSRIKISNGRTTYAGSVKGRFTISSDNAKNTVYLQMNSLNAEDTAVYYCAADRSSLLFGSNWDRKARYDYWGQGTQ VTVSS OX40L009 192EVQLVESGGGLVQAGGSLRLSCAASGFTLDDYAIAWFRQAPGKEREGV (OX40L19A07-SRIKISNGRTTYAGSVKGRFTISSDNAKNTVYLQMNSLNAEDTAVYYC 9GS-Alb8-9GS-AADRSSLLFGSNWDRKARYDYWGQGTQVTVSSGGGGSGGGSEVQLVES OX40L19A07)GGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQAGGSLRLSCAASGFTLDDYAIAWFRQAPGKEREGVSRIKISNGRTTYAGSVKGRFTISSDNAKNTVYLQMNSLNAEDTAVYYCAADRSSLLFGSNWDRKARYDYWGQGTQ VTVSS OX40L033 193EVQLVESGGGLVQAGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREF (OX40L01E07VAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYY (Q108L)-35GS-CAAVGGATTVTASEWDYWGLGTLVTVSSGGGGSGGGGSGGGGSGGGGS OX40L01E07GGGGSGGGGSGGGGSEVQLVESGGGLVQAGGSLRLSCAASGRTFSSIY (Q108L)-AKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVY 9GS-ALB11)LQMNSLKPEDTAVYYCAAVGGATTVTASEWDYWGLGTLVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTA VYYCTIGGSLSRSSQGTLVTVSSOX40L034 194 EVQLVESGGGLVQAGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREF(OX40L01E07 VAAISRSGRSTSYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYY(Q108L)-35GS- CAAVGGATTVTASEWDYWGLGTLVTVSSGGGGSGGGGSGGGGSGGGGSOX40L01E07 GGGGSGGGGSGGGGSEVQLVESGGGLVQAGGSLRLSCAASGRTFSSIY(Q108L)-35GS- AKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNAKNTVY ALB11)LQMNSLKPEDTAVYYCAAVGGATTVTASEWDYWGLGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVS S OX40L035 195EVQLVESGGGLVQAGDSLRLSCAASGLTFSSFAMGWFRQAPGKEREFV (OX40L01E10AAISRSGYGTSEADSVRDRFIISRDNAKNTVTLHLSRLKPEDTAVYYC (Q108L)-35GS-AAEHTLGRPSRSQINYLYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGG OX40L01E10SGGGGSGGGGSGGGGSEVQLVESGGGLVQAGDSLRLSCAASGLTFSSF (Q108L)-9GS-AMGWFRQAPGKEREFVAAISRSGYGTSEADSVRDRFIISRDNAKNTVT ALB11)LHLSRLKPEDTAVYYCAAEHTLGRPSRSQINYLYWGQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSS OX40L036 196EVQLVESGGGLVQAGDSLRLSCAASGLTFSSFAMGWFRQAPGKEREFV (OX40L01E10AAISRSGYGTSEADSVRDRFIISRDNAKNTVTLHLSRLKPEDTAVYYC (Q108L)-35GS-AAEHTLGRPSRSQINYLYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGG OX40L01E10SGGGGSGGGGSGGGGSEVQLVESGGGLVQAGDSLRLSCAASGLTFSSF (Q108L)-35GS-AMGWFRQAPGKEREFVAAISRSGYGTSEADSVRDRFIISRDNAKNTVT ALB11)LHLSRLKPEDTAVYYCAAEHTLGRPSRSQINYLYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVT VSS OX40L037 197EVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHRTGEPRELV (OX40L015B07ATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPEDTAVYYCN (Q108L)-35GS-FNKYVTSRDTWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGG OX40L015B07GGSGGGGSEVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHR (Q108L)-9GS-TGEPRELVATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPE ALB11)DTAVYYCNFNKYVTSRDTWGQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSS QGTLVTVSS OX40L038 198EVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHRTGEPRELV (OX40L015B07ATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPEDTAVYYCN (Q108L)-35GS-FNKYVTSRDTWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGG OX40L015B07GGSGGGGSEVQLVESGGGLVQAGGSLRLSCAASRSIGRLDRMGWYRHR (Q108L)-35GS-TGEPRELVATITGGSSINYGDFVKGRFTISIDNAKNTVYLQMNNLKPE ALB11)DTAVYYCNFNKYVTSRDTWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSS

TABLE A-4 Preferred sequence optimized polypeptide or compound sequencesSEQ Name ID NO Amino acid sequence OX40L032 227EVQLVESGGGLVQPGGSLRLSCAASGRSFSTYIMGWFRQAPGKEREFV (OX40L01B11ATISRSGITTRSADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYYC (A14P, V23A, AAGPYVEQTLGLYQTLGPWDYWGQGTLVTVSSGGGGSGGGGSGGGGSG A74S, K83R,GGGSGGGGSGGGGSGGGGSEVOLVESGGGLVQPGGSLRLSCAASGRSF Q108L)-35GS-STYIMGWFRQAPGKEREFVATISRSGITTRSADSVKGRFTISRDNSKN OX40L01B11TVYLQMNSLRPEDTAVYYCAAGPYVEQTLGLYQTLGPWDYWGQGTLVT (A14P, V23A,VSSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVOLVESGGG A74S, K83R,LVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDT Q108L)-35GS-LYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSS ALB11) QGTLVTVSSOX40L051 228 EVQLVESGGGLVQPGGSLRLSCAASGRSFSTYIMGWFRQAPGKEREFV(OX40L01B11 ATISRSGITTRSADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYYC(A14P, V23A, AAGPYVEQTLGLYQTLGPWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGA74S, K83R, GGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFQ108L)-35GS- SSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTALB11-35GS- TLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGGS OX40L01B11GGGGSGGGGSGGGGSGGGGSGGGGSEVOLVESGGGLVQPGGSLRLSCA (A14P, V23A,ASGRSFSTYIMGWFRQAPGKEREFVATISRSGITTRSADSVKGRFTIS A74S, K83R,RDNSKNTVYLQMNSLRPEDTAVYYCAAGPYVEQTLGLYQTLGPWDYWG Q108L)) QGTLVTVSSOX40L079 229 DVQLVESGGGLVQPGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREF(OX40L01E07 VAAISRSGRSTSYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYY (E1D, A14P,CAAVGGATTVTASEWDYWG0GTLVTVSSGGGGSGGGGSGGGGSGGGGS A74S, K83R, GGGGSGGGGSGGGGSEVQLVESGGGLVQPGGSLRLSCAASGRTFSSIY L105Q, Q108L)-AKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDNSKNTVY 35GS-LQMNSLRPEDTAVYYCAAVGGATTVTASEWDYWGQGTLVTVSSGGGGS OX40L01E07GGGGSGGGGSGGGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSL (A14P, A74S,RLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKG K83R, L105Q,RFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVS Q108L)-35GS- S ALB11)OX40L080 230 DVQLVESGGGLVQPGGSLRLSCAASGRTFSSIYAKGWFRQAPGKEREF(OX40L01E07 VAAISRSGRSTSYADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYY (E1D, A14P,CAAVGGATTVTASEWDYWGQGTLVTVSSGGGGSGGGGSGGGGSGGGGS A74S, K83R,GGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTFSSFG L105Q, Q108L)-MSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKTTLYL 35GS-ALB11-QMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGGSGGGG 35GS-SGGGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGGSLRLSCAASGR OX40L01E07TFSSIYAKGWFRQAPGKEREFVAAISRSGRSTSYADSVKGRFTISRDN (A14P, A74S, SKNTVYLQMNSLRPEDTAVYYCAAVGGATTVTASEWDYWGQGTLVTVS K83R, L105Q, S Q108L))OX40L084  231 DVQLVESGGGLVQPGGSLRLSCAASRSIGRLDRMGWYRHRPGEPRELV(OX40L15B07 ATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNSLRPEDTAVYYCN (E1D, A14P,ENKYVTSRDTWG0GTLVTVSSGGGGSGGGSEVOLVESGGGLVQPGNSL T41P, F62S, RLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKG A74S, N82bS, RFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVS K83R, Q108L)-SGGGGSGGGSEVQLVESGGGLVQPGGSLRLSCAASRSIGRLDRMGWYR 9GS-ALB11-9GS-HRPGEPRELVATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNSLR A14P, T41P, PEDTAVYYCNFNKYVTSRDTWGQGTLVTVSS F62S, A74S,  N82bS, K83R,  Q108L))OX40L085  232 DVQLVESGGGLVQPGGSLRLSCAASRSIGRLDRMGWYRHRPGKPRELV(OX40L15B07 ATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNSLRPEDTAVYYCN(E1D, A14P,  FNKYVTSRDTWGQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQPGNSLT41P, E43K,  RLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGF62S, A74S,  RFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSN82bS, K83R,  SGGGGSGGGSEVQLVESGGGLVQPGGSLRLSCAASRSIGRLDRMGWYRQ108L)-9GS- HRPGKPRELVATITGGSSINYGDSVKGRFTISIDNSKNTVYLQMNSLR ALB11-9GS-PEDTAVYYCNFNKYVTSRDTWGQGTLVTVSS OX40L15B07 (A14P, T41P,  E43K, F62S, A74S, N82bS,  K83R, Q108L)) OX40L086  233DVQLVESGGGLVQPGGSLRLSCAASGRSFSTYIMGWFRQAPGKEREFV (OX40L01B11ATISRSGITTRSADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYYC (E1D, A14P, AAGPYVEQTLGLYQTLGPWDYWGQGTLVTVSSGGGGSGGGGSGGGGSG V23A, A74S, GGGSGGGGSGGGGSGGGGSEVQLVESGGGLVQPGNSLRLSCAASGFTF K83R, Q108L)-SSFGMSWVRQAPGKGLEWVSSISGSGSDTLYADSVKGRFTISRDNAKT 35GS-ALB11-TLYLQMNSLRPEDTAVYYCTIGGSLSRSSQGTLVTVSSGGGGSGGGGS 35GS-GGGGSGGGGSGGGGSGGGGSGGGGSEVOLVESGGGLVQPGGSLRLSCA OX40L01B11ASGRSFSTYIMGWFRQAPGKEREFVATISRSGITTRSADSVKGRFTIS (A14P, V23A, RDNSKNTVYLQMNSLRPEDTAVYYCAAGPYVEQTLGLYQTLGPWDYWG A74S, K83R,  QGTLVTVSSQ108L)) OX40L095  234 DVQLVESGGGLVQPGGSLRLSCAASGRSFSTYIMGWFRQAPGKEREFV(OX40L01B11 ATISRSGITTRSADSVKGRFTISRDNSKNTVYLQMNSLRPEDTAVYYC (E1D, A14P,AAGPYVEQTLGLYQTLGPWDYWGQGTLVTVSSGGGGSGGGSEVQLVES V23A, A74S, GGGLVQPGNSLRLSCAASGFTFSSFGMSWVRQAPGKGLEWVSSISGSG K83R, Q108L)-SDTLYADSVKGRFTISRDNAKTTLYLQMNSLRPEDTAVYYCTIGGSLS 9GS-ALB11-9GS-RSSQGTLVTVSSGGGGSGGGSEVQLVESGGGLVQPGGSLRLSCAASGR OX40L01B11SFSTYIMGWFRQAPGKEREFVATISRSGITTRSADSVKGRFTISRDNS (A14P, V23A, KNTVYLQMNSLRPEDTAVYYCAAGPYVEQTLGLYQTLGPWDYWGQGTL A74S,K83R,  VTVSSQ108L))

TABLE A-5 Further sequences SEQ ID Name NO: Amino acid sequencehuman OX40L 175 MERVQPLEENVGNAARPRFERNKLLLVASVIQGLGLLLCFTYICLHFSALQVSHRY PRIQSIKVQFTEYKKEKGFILTSQKEDEIMKVQNNSVIINCDGFYLISLKGYFSQE VNISLHYQKDEEPLFQLKKVRSVNSLMVASLTYKDKVYLNVTTDNTSLDDFHVNGG ELILIHQNPGEFCVL cynomolgus 176MERVQPLEENVGNAARPRFERNKLLLVA OX40L SVIQGLGLLLCFTYICLHFSALQVSHQYPRIQSIKVQFTEYKKEEGFILTSQKEDE IMKVQNNSVIINCDGFYLISLKGYFSQEVNISLHYQKDEEPLFQLKKVRSVNSLMV ASLTYKDKVYLNVTTDNTSLDDFHVNGGELILIHQNPGEFCVL OX40L 177 EVCILLESGGGLVQPGGSLRLSCAASGF benchmarkTFNSYAMSWVRQAPGKGLEWVSIISGSG antibody GFTYYADSVKGRFTISRDNSRTTLYLQM heavyNSLRAEDTAVYYCAKDRLVAPGTFDYWG chain QGALVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALT SGVHTFPAVLOSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSC DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFN WYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPI EKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPE NNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLS PGK OX40L 178 DIQMTQSPSSLSASVGDRVTITCRASQGbenchmark ISSWLAWYQQKPEKAPKSLIYAASSLQS antibodyGVPSRFSGSGSGTDFTLTISSLQPEDFA light TYYCQQYNSYPYTFGQGTKLEIKRTVAA chainPSVFIFPPSDEQLKSGTASVVCLLNNFY PREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEV THQGLSSPVTKSFNRGEC

TABLE C-1 Blocking capacity of Nanobodies in AlphaScreen and FACShOX40L/hOX40 AlphaScreen FACS ID IC50 (pM) IC50 (nM) OX40L01B11 375 5.61OX40L01E07 423 8.89 OX40L01E10 490 9.11 OX40L15B07 300 1.61 OX40L18E09112 1.73 OX40L19A07 540 16.55 OX40L19D08 285 3.31 benchmark Fab 1970217.28

TABLE C-2 IC50 values for Nanobodies in OX40L mediated T-cell activationassay donor 1 donor 2 donor 3 donor 4 ID IC50 (nM) IC50 (nM) IC50 (nM)IC50 (nM) OX40L01B11 230 188 80 220 OX40L01E07 260 320 125 169OX40L01E10 110 159 27 12 OX40L15B07 236 249 73 n.d. OX40L18E09 36 45 3649 OX40L19A07 596 618 n.d. n.d. OX40L19D08 90 132 36 96 Benchmark 80 13158 85 Fab nd: not determined

TABLE C-3 Binding of Nanobodies to cell expressed OX40L Binding toBinding to CHO-hOX40L CHO-cynoOX40L ID EC50 (nM) EC50 (nM) OX40L01B112.94 3.39 OX40L01E07 4.03 4.90 OX40L01E10 3.77 5.54 OX40L15B07 2.43 3.23OX40L18E09 2.26 3.80 OX40L19A07 5.67 5.34 OX40L19D08 2.85 3.40

TABLE C-4 Potency of trivalent Nanobodies in AlphaScreen and FACShOX40L/hOX40 AlphaScreen IC50 (pM) in presence FACS ID IC50 (pM) of HSAIC50 (nM) OX40L01E10 264 n.d. 12 OX40L006 70 122 18 OX40L035 35 35 n.d.OX40L036 40 40 n.d. OX40L01B11 278 n.d. 5 OX40L009 17 22 2 OX40L01E07229 n.d. 11 OX40L003 61 85 16 OX40L033 50 50 n.d. OX40L034 40 40 n.d.OX40L18E09 41 n.d. 2 OX40L004 20 25 4 OX40L19A07 355 n.d. 13 OX40L008 95126 17 OX40L19D08 133 n.d. 4 OX40L005 32 41 7 OX40L15B07 125 n.d. 2OX40L007 14 17 2 OX40L037 13 13 n.d. OX40L038 11 11 n.d. nd: notdetermined

TABLE C-5 Binding of trivalent Nanobodies to Human Serum Albumin ka kdKD ID 1/Ms 1/s nM OX40L006 1.30E+05 4.70E−03 36.6 OX40L009 1.80E+054.70E−03 25.8 OX40L003 7.30E+05 5.00E−03 6.9 OX40L034 9.30E+05 6.00E−036.4 OX40L004 5.00E+05 4.20E−03 8.3 OX40L008 4.40E+05 3.90E−03 8.8OX40L005 3.70E+05 4.70E−03 12.9 OX40L007 3.30E+05 4.90E−03 14.9

TABLE C-6 IC50 values for trivalent Nanobodies in OX40L mediated T-cellactivation assay donor 5 donor 6 donor 7 donor 8 donor 1 donor 2 donor 3donor 4 IC50 IC50 IC50 IC50 IC50 IC50 IC50 IC50 (nM) (nM) (nM) (nM) ID(nM) (nM) (nM) (nM) +10% HS +10% HS +10% HS +10% HS OX40L006 3.6 3.4 1.61.1 27.2 10.4 nd 2.9 OX40L035 nd nd nd nd 7.1 1.6 nd 1.4 OX40L036 nd ndnd nd 10.6 0.7 1.0 1.7 OX40L009 nd nd 0.1 0.03 nd nd nd nd OX40L003 18.86.4 4.7 5.2 nd nd 48.3 12.5 OX40L033 nd nd nd nd 11.9 2.4 3.5 2.3OX40L034 nd nd nd nd 8.3 nd 0.8 0.8 OX40L004 nd nd 0.7 0.8 nd nd nd ndOX40L008 nd nd nd nd nd nd nd nd OX40L005 nd nd 0.2 2.8 nd nd nd ndOX40L007 nd nd 0.3 0.3 1.1 0.8 1.6 0.3 OX40L037 nd nd nd nd 1.4 0.6 0.81.0 OX40L038 nd nd nd nd 0.8 1.6 nd 0.6 benchmark Fab 80.2 130.9 57.685.2 nd nd nd nd benchmark IgG 69.1 57.2 35.1 5.6 nd nd nd nd nd: notdetermine HS: human serum

TABLE C-7 Competition of Nanobodies with anit-OX40L benchmark FabAdditional binding of % of expected ID LC001 Fab (RU) LC001Fab bindingOX40L01B11 14 4 OX40L01E10 109 27 OX40L15B07 80 20 OX40L18E09 70 18OX40L19D08 218 55 OX40L19A07 160 40 OX40L01E07 232 58

TABLE C-8 Competition of Nanobodies with each other Binding BindingBinding Level Level Level sample 2 − First Second sample 1 sample 2sample 1 injection injection (RU) (RU) (RU) OX40L01B11 HBS-EP+ 440 383−57 OX40L01B11 373 380 7 OX40L01E10 349 342 −7 OX40L15B07 332 324 −9OX40L18E09 319 312 −7 OX40L19D08 309 468 159 OX40L19A07 301 371 70OX40L01E07 292 486 194 OX40L01E10 HBS-EP+ 211 185 −26 OX40L01B11 220 29676 OX40L01E10 207 215 8 OX40L15B07 219 237 17 OX40L18E09 224 245 21OX40L19D08 226 275 49 OX40L19A07 227 239 12 OX40L01E07 227 289 62OX40L15B07 HBS-EP+ 195 155 −40 OX40L01B11 199 259 61 OX40L01E10 185 1905 OX40L15B07 194 198 5 OX40L18E09 197 207 11 OX40L19D08 197 239 42OX40L19A07 198 207 9 OX40L01E07 198 252 55 OX40L18E09 HBS-EP+ 185 168−16 OX40L01B11 190 238 48 OX40L01E10 178 176 −2 OX40L15B07 187 189 2OX40L18E09 190 195 5 OX40L19D08 192 224 33 OX40L19A07 192 194 2OX40L01E07 192 238 45 OX40L19D08 HBS-EP+ 222 184 −38 OX40L01B11 227 433205 OX40L01E10 215 202 −13 OX40L15B07 224 217 −7 OX40L18E09 227 225 −3OX40L19D08 229 236 7 OX40L19A07 229 205 −24 OX40L01E07 229 252 23OX40L19A07 HBS-EP+ 175 160 −15 OX40L01B11 178 358 180 OX40L01E10 166 18317 OX40L15B07 174 200 26 OX40L18E09 176 206 30 OX40L19D08 177 224 47OX40L19A07 177 183 6 OX40L01E07 177 240 63 OX40L01E07 HBS-EP+ 220 212 −9OX40L01B11 194 399 205 OX40L01E10 188 193 5 OX40L15B07 186 198 12OX40L18E09 185 200 15 OX40L19D08 184 187 3 OX40L19A07 182 179 −3OX40L01E07 181 192 11

TABLE C-9 Potency and melting temperature of OX40L01B11 variantAlphascreen hOX40L/hOX40: IC50 (nM) TSA ID Native Tm + 10° C. T_(m) (°)at pH 7.5 OX40L01B11 0.54 0.6 69.79 OX40L075 0.31 1.9 67.3

TABLE C-10 Potency and melting temperature of OX40L01E07 variantsAlphascreen T cell assay hOX40L/hOX40: with rec. IC50 (PM) hOX40L: TSAID Native Tm + 10° C. IC50 (nM) Tm (°) at pH 7.5 OX40L01E07 100 100 1.4873.2 OX40L024 70 70 1.54 71.1 OX40L025 60 50 1.15 71.5 OX40L026 50 602.46 76.1 OX40L027 70 70 1.43 76.5 OX40L028 70 70 2.3 71.9 OX40L039 5050 1.6 76.1

TABLE C-11 Potency and melting temperature of OX40L15B07 variantsAlphascreen T cell hOX40L/hOX40: Alphascreen Alphascreen assay TSA IC₅₀(nM)- hOX40L/hOX40: hOX40L/hOX40: with rec. Tm assay1 IC₅₀ (nM)- assay 2IC₅₀ (nM)- assay 3 hOX40L (° C. at ID Native Native Tm + 10° C. NativeTm + 10° C. IC₅₀ (nM) pH 7.5) OX40L15B07 0.102 0.066 0.103 0.077 nd 1069.85 OX40L030 0.076 nd nd 0.143 0.143 11 70.67 OX40L040 0.046 0.0920.084 0.102 0.082 9 63.6 OX40L041 0.127 0.22  0.262 nd nd 64 58.2OX40L042 0.057 nd nd nd nd 18 66.1 OX40L043 0.101 0.134 0.156 nd nd 2964.85 OX40L044 0.065 nd nd nd nd 76 60.28 OX40L045 0.152 nd nd nd nd 13362.36 OX40L046 0.084 0.256 0.221 nd nd 57 67.76 OX40L047 0.269 0.7350.557 nd nd 126 65.68 OX40L048 0.093 0.314 0.314 nd nd 32 63.19 OX40L0490.035 nd nd nd nd 12 63.99 OX40L050 0.046 0.145 0.164 nd nd 43 63.6OX40L053 nd nd nd 0.118 0.126 nd 68.57 OX40L054 nd nd nd 0.079 0.094 nd63.58 OX40L055 nd nd nd 0.091 0.106 nd 65.66 OX40L056 nd 1.124 1.1241.124 1.124 135 67.32 OX40L082 nd nd nd 0.14  0.14  nd 71.87 nd: notdetermined

TABLE C-12 IC50 values obtained for trivalent sequence optimizedNanobodies in OX40L mediated T-cell activation assay donor 9 donor 10donor 11 donor 12 donor 13 IC50 IC50 IC50 IC50 IC50 IC50 IC50 IC50 IC50IC50 (nM) (nM) (nM) (nM) (nM) (nM) (nM) (nM) (nM) (nM) ID +10% FBS +10%HS +10% FBS +10% HS +10% FBS +10% HS +10% FBS +10% HS +10% FBS +10% HS OX40L003 nd nd nd nd 10.9 106.0 11.0 64.2 nd nd OX40L034 nd nd nd nd 6.426.4 7.9 24.5 nd nd OX40L079 nd nd nd nd 5.3 19.3 5.5 7.1 nd nd OX40L080nd nd nd nd 6.9 30.5 6.2 13.4 nd nd OX40L007 nd nd 7.9 11.5 nd nd 3.0 nd4.1 9.8 OX40L084 nd nd 15.2 13.9 nd nd 3.6 5.0 12.0 7.8 OX40L085 nd nd123.0 49.4 nd nd 62.8 nd nd nd OX40L009 5.6 9.9 7.7 20.3 nd nd nd nd ndnd OX40L032 5.2 8.9 9.4 12.1 nd nd nd nd nd nd OX40L051 4.0 3.9 5.8 7.9nd nd nd nd 2.3 3.6 OX40L086 nd nd nd nd nd nd nd nd 4.2 5.1 anti-OX40Lnd nd 203.0 161.0 61.2 30.2 22.1 42.9 84.4 120.5 benchmark IgG nd: notdetermined

TABLE C-13 Binding of trivalent sequence optimiezed Nanobodies to HumanSerum Albumin BIAcore kinetic analysis on HSA ID ka (1/Ms) kd (1/s) KD(nM) OX40L003 7.30E+05 5.00E−03 6.9 OX40L034 9.30E+05 6.00E−03 6.4OX40L079 6.90E+05 6.00E−03 8.7 OX40L080 7.20E+05 5.40E−03 7.6 OX40L0073.30E+05 4.90E−03 14.9 OX40L084 4.20E+05 4.10E−03 9.7 OX40L085 8.00E+053.90E−03 4.9 OX40L009 1.80E+05 4.70E−03 25.8 OX40L0032 1.80E+05 6.00E−0333 OX40L051 1.90E+05 5.30E−03 27

The invention claimed is:
 1. Immunoglobulin single variable domain thatspecifically binds to OX40L (SEQ ID NO: 175), in which CDR1 is SEQ IDNO:134; CDR2 is SEQ ID NO:148; CDR3 is SEQ ID NO:162; wherein theimmunoglobulin single variable domain is a VH domain, a VHH, a partiallyhumanized VHH or a fully humanized VHH.
 2. The immunoglobulin singlevariable domain according to claim 1, that can specifically bind toOX40L (SEQ ID NO: 175), with a dissociation constant (KD) of 10-5 to10-12 moles/liter or less, with a rate of association (kon-rate) ofbetween 102 M-1s-1 to about 107 M-1s-1, with a rate of dissociation(koff rate) between 1 s-1 and 10-6 s-1, with an affinity of less than500 nM, having an IC50 value in an Amplified Luminescent ProximityHomogeneous Assay with 0.12 nM hOX40L and 0.2 nM OX40/Fc of less than 10nM, having an IC50 value in the FACS assay of less than 100 nM, and/orhaving an IC50 value in the T-cell activation assay using human donorsthat is less than the IC50 of the benchmark Fab (SEQ ID NO: 177 and 178,representing the polypeptides of the heavy and light chain,respectively).
 3. The immunoglobulin single variable domain according toclaim 1, wherein said immunoglobulin single variable domain is chosenfrom the group consisting of SEQ ID NO: 180; SEQ ID NO: 199;immunoglobulin single variable domains that cross-block the binding toOX40L of at least one of SEQ ID NOs: 188 and 199, and immunoglobulinsingle variable domains that are cross-blocked from binding to OX40L byat least one of SEQ ID NOs: 188 and
 199. 4. Polypeptide that comprisesor essentially consists of one or more immunoglobulin single variabledomains according to claim
 1. 5. The polypeptide according to claim 4that is SEQ ID NO:
 228. 6. The polypeptide according to claim 4, whichfurther comprises one or more other residues or binding units,optionally linked via one or more peptidic linkers.
 7. The polypeptideaccording to claim 6, in which said one or more other residues orbinding units are chosen from the group consisting of immunoglobulinsequences, domain antibodies, and single domain antibodies.
 8. Thepolypeptide according to claim 6, which is a multivalent construct, amultispecific construct, a multiparatopic construct, and/or has anincreased half-life, compared to the corresponding immunoglobulin singlevariable domain.
 9. The polypeptide according to claim 8, in which saidone or more other binding units provide the polypeptide with increasedhalf-life, compared to the corresponding immunoglobulin single variabledomain.
 10. The polypeptide according to claim 9, in which said one ormore other binding units that provide the polypeptide with increasedhalf-life are chosen from the group consisting of binding units that canbind to serum albumin, human serum albumin, a serum immunoglobulin, IgG,domain antibodies, single domain antibodies, single domain antibodiesthat can bind to serum albumin, and single domain antibodies that canbind to human serum albumin.
 11. Nucleic acid or nucleotide sequence,that encodes an immunoglobulin single variable domain according toclaim
 1. 12. Host or host cell that expresses, or that under suitablecircumstances is capable of expressing, an immunoglobulin singlevariable domain according to claim
 1. 13. Composition comprising atleast one immunoglobulin single variable domain according to claim 1.14. The composition according to claim 13, further comprising a carrier.15. Method for producing an immunoglobulin single variable domainaccording to claim 1, said method at least comprising the step of:expressing, in a suitable host cell or host organism or in anothersuitable expression system, a nucleic acid or nucleotide sequenceencoding the an immunoglobulin single variable domain; optionallyfollowed by isolating and/or purifying the immunoglobulin singlevariable domain.
 16. Method for screening polypeptides that specificallybind to OX40L that comprises at least the steps of: a) providing a set,collection or library of nucleic acids encoding polypeptides; b)screening said set, collection or library of nucleic acids for a nucleicacid that encodes a polypeptide that can bind to and/or has affinity forOX40L and that cross blocks an immunoglobulin single variable domaincomprising SEQ ID NO: 180, or the humanized and/or sequence optimizedimmunoglobulin single variable domain of SEQ ID NO: 199, or thepolypeptide or construct of SEQ ID NO: 228; and c) isolating saidnucleic acid, followed by expressing said polypeptide.
 17. Animmunoglobulin single variable domain that specifically binds to OX40L,which consists of 4 framework regions (FR1 to FR4, respectively) and 3complementarity determining regions (CDR1 to CDR3, respectively),wherein: (a) CDR1 is SEQ ID NO: 134; CDR2 is SEQ ID NO: 148; and CDR3 isSEQ ID NO: 162; or (b) CDR1 has 3, 2, or 1 amino acid difference withSEQ ID NO: 134; CDR2 has 3, 2, or 1 amino acid difference with SEQ IDNO: 148; and CDR3 is SEQ ID NO: 162; wherein the immunoglobulin singlevariable domain is a VH domain, a VHH, a partially humanized VHH or afully humanized VHH.
 18. An immunoglobulin single variable domain thatspecifically binds to OX40L, which consists of 4 framework regions (FR1to FR4, respectively) and 3 complementarity determining regions (CDR1 toCDR3, respectively), in which CDR1 has 3, 2, or 1 amino acid differencewith SEQ ID NO: 134; CDR2 is SEQ ID NO: 148; and CDR3 is SEQ ID NO: 162;wherein the immunoglobulin single variable domain is a VH domain, a VHH,a partially humanized VHH or a fully humanized VHH.
 19. Animmunoglobulin single variable domain that specifically binds to OX40L,which consists of 4 framework regions (FR1 to FR4, respectively) and 3complementarity determining regions (CDR1 to CDR3, respectively), inwhich CDR1 is SEQ ID NO: 134; CDR2 has 3, 2, or 1 amino acid differencewith SEQ ID NO: 148; and CDR3 is SEQ ID NO: 162; wherein theimmunoglobulin single variable domain is a VH domain, a VHH, a partiallyhumanized VHH or a fully humanized VHH.
 20. An immunoglobulin singlevariable domain that specifically binds to OX40L, which consists of 4framework regions (FR1 to FR4, respectively) and 3 complementaritydetermining regions (CDR1 to CDR3, respectively), in which CDR1 is SEQID NO: 134; CDR2 is SEQ ID NO: 148; and CDR3 has 3, 2, or 1 amino aciddifference with SEQ ID NO: 162; wherein the immunoglobulin singlevariable domain is a VH domain, a VHH, a partially humanized VHH or afully humanized VHH.